The Long Barrow and Dolman Enigma

February 6, 2026 Trebor2510

Contents

1 Rethinking Long Barrows, Dolmens, and the Forgotten Maritime World of Prehistoric Britain
2 Section 8 – What This Changes
- 2.1 Conclusion – Long Barrows Reframed
- 2.2 Why Archaeology Missed This
3 Appendix – Earliest Secure Dates of Megalithic Monuments by Country (Summary)
- 3.1 Appendix — Earliest Secure Dates by Country (Top 5 per country)
- 3.2 Methods — How we calculated the BCE ranges (and why older books are off)
4 Full List of C14 dates
5 Our Approach and Dates
6 Appendix – Case Study: Arthur’s Stone and Controlled Excarnation Landscapes
7 PodCast
8 Author’s Biography
9 Exploring Prehistoric Britain: A Journey Through Time
10 Further Reading
11 Other Blogs

Rethinking Long Barrows, Dolmens, and the Forgotten Maritime World of Prehistoric Britain

Introduction: Reassembling a Broken Argument

This article deliberately replaces three earlier, separate blog posts on prehistoric-britain.co.uk:

The Long Barrow Mystery: Unravelling Ancient Connections
The Dolmen and Long Barrow Connection

Those essays were written years apart and explored different aspects of the same unresolved problem. Read individually, they raised important questions. Read together, they exposed a much larger failure in how long barrows are interpreted at all. (The Long Barrow and Dolman Enigma)

The purpose of this new, consolidated work is not to repeat those articles, but to finish the argument they collectively began.

Long barrows are still presented in mainstream archaeology as simple early Neolithic burial mounds, built by small, sedentary farming communities, functioning primarily as ritual or symbolic tombs. That explanation has survived largely because it has never been tested against the full set of observable constraints: landscape position, hydrology, visibility, geometry, standardisation, and continuity across regions.

When those constraints are applied consistently, the orthodox interpretation collapses.

What emerges instead is a coherent, testable alternative: long barrows were not isolated funerary constructions, but deliberate, standardised monuments embedded within a water-dominated post-glacial landscape. Their form, placement, materials, and orientation only make sense when Britain is understood as a semi-flooded, river-linked environment where movement, trade, and visibility were primarily maritime.

This article, therefore, does three things in order:

It demonstrates why the conventional explanation fails.
It shows that long barrows and dolmens belong to the same structural tradition.
It reinterprets long barrows as monuments of a boat-based civilisation whose worldview, transport systems, and mortuary practices were inseparable.

This is not a symbolic reading imposed after the fact. It is a landscape-led reconstruction based on form and function.

Once that lens is applied, long barrows stop being mysterious.

They become inevitable.

1. The Problem with the Conventional Explanation

The orthodox archaeological explanation for long barrows is deceptively simple: they are described as early Neolithic communal burial mounds, constructed by newly sedentary farming communities, serving primarily ritual or symbolic purposes.

This narrative persists not because it explains the evidence well, but because it has rarely been challenged as a system.

When examined closely, the conventional model fails on multiple, independent fronts.

First, it cannot explain standardisation. Long barrows across Britain—and far beyond—exhibit remarkably consistent proportions, layouts, and orientations. This level of repeatability implies shared design rules, not ad‑hoc ritual expression by isolated groups.

Second, it fails to cite. Long barrows are rarely positioned where burial alone would be most practical or socially central. They are commonly placed on slopes, ridgelines, valley edges, and liminal zones—often overlooking river systems or low‑lying ground. These are poor choices for purely funerary monuments, but excellent choices for visibility and signalling.

Third, it fails on landscape logic. The orthodox model treats the early Neolithic landscape as essentially dry and terrestrial. Yet mounting geological, geomorphological, and hydrological evidence shows that early Holocene Britain was dominated by elevated water tables, wide braided rivers, floodplains, and seasonal inundation. Any interpretation that ignores this context is incomplete by definition.

Fourth, it fails on the grounds of function creep. When aspects of long barrows do not fit the burial narrative—chalk cladding, exaggerated length, pointed ends, flanking ditches—they are dismissed as symbolic embellishments rather than design features requiring explanation. Symbolism becomes a refuge for unanswered questions.

Finally, the orthodox model cannot explain change over time. If long barrows are simply tombs, why are they replaced by round barrows that abandon elongation, directionality, and visibility? The transition reflects a change in environmental and social conditions, not merely belief.

In short, the conventional explanation does not fail because it is wrong in detail, but because it is structurally incomplete. It isolates burial from movement, landscape from function, and monument form from environment.

Any credible reinterpretation must therefore begin elsewhere: not with ritual assumptions, but with observable constraints imposed by geography, water, and human movement.

2. The Shape That Refuses to Be Accidental

Before questions of burial, belief, or ritual are even entertained, long barrows present a more basic problem — one of geometry.

Long barrows are not amorphous mounds. They are not circular, irregular, or locally improvised. They are elongated, axial, directional structures with consistent proportions that recur across regions separated by hundreds of kilometres.

This alone should have disqualified casual explanations.

Standardisation Without Central Authority

Across Britain, long barrows repeatedly exhibit:

Pronounced elongation along a single axis
A narrower, tapered end and a broader terminal end
Chambers concentrated toward one end, not the centre
Flanking ditches running parallel to the long axis

This is standardisation without masonry, achieved using earth, chalk, timber, and stone.

Such consistency implies:

Shared design principles
Transmitted knowledge
A functional reason to preserve proportions

Ritual expression does not require this level of constraint. Engineering does.

The Boat Problem

Once seen, the comparison is unavoidable.

In plan, profile, and proportion, long barrows replicate the essential geometry of a boat:

A pointed or narrowing bow
A broader stern
A dominant longitudinal axis
A structure designed to be approached from one direction

This resemblance is not metaphorical. It is structural.

Crucially, this geometry appears before later symbolic embellishments and survives regional stylistic variation. That indicates priority of form over decoration.

Directionality and Movement

Long barrows are rarely neutral in orientation.

They frequently:

Face downslope
Align toward valleys or floodplains
Present their narrow end toward low ground

This makes little sense for tombs intended for static commemoration.

It makes perfect sense for monuments intended to be seen, approached, or conceptually entered from a water-dominated landscape.

In a world where rivers were transport corridors, direction mattered.

Why This Was Missed

Archaeology has historically separated monument form from movement.

Long barrows were interpreted from a standing position on dry land, not from a moving viewpoint within a flooded or semi-flooded landscape.

From water level, the elongated silhouette, tapering profile, and chalk brightness would have been legible instantly.

From a ploughed field, they appear inert.

Geometry as Constraint, Not Symbol

The key error has been to treat long barrow shape as symbolic choice rather than functional constraint.

Symbols vary.

Constraints repeat.

Long barrows repeat because their geometry solved a real-world problem — one tied to movement, visibility, and orientation in a landscape dominated by water.

Only once this is understood can burial practices be meaningfully reintroduced into the discussion.

3. Dolmens Reconsidered: Excarnation, Not Stripped Long Barrows

Structural Design: Why True Dolmens Are Not Buried Monuments

A critical distinction has been missed by archaeology because monuments have been grouped by visual similarity rather than mechanical design.

A true dolmen is defined not by appearance, but by load mechanics.

Across multiple surviving examples, dolmens share a set of engineering features that are incompatible with burial:

Upright stones are point-loaded, tapering to minimal contact areas
Capstones rest on rock points, not flat lintels
Load paths are vertical and concentrated, not distributed
The structure has no resistance to lateral soil pressure
Capstones are often angled or convex, not horizontal

These features are deliberate. They allow the structure to carry the capstone alone — and nothing more.

If an earthen mound were placed over such a structure, the result would be predictable and rapid failure through inward rotation and shear at the contact points. This is basic structural physics.

By contrast, long barrow chambers use flat orthostats, horizontal lintels, and distributed bearing surfaces precisely because they were designed to be buried.

The two designs solve opposite engineering problems.

This alone falsifies the long-standing claim that dolmens are simply long barrows with their mounds removed.A critical correction is required here, because the common archaeological assumption — and my earlier framing — is wrong.

Dolmens are not simply long barrows with their earthen mounds removed. That interpretation fails on basic structural, mechanical, and functional grounds.

Once construction details are examined properly, dolmens resolve into a different monument class entirely, serving a different mortuary purpose.

Structural Incompatibility with Long Barrows

Long barrow chambers are engineered to carry immense dead load.

Orthostats are upright but square-edged or flat-topped
Lintels are horizontal and load-bearing
Capstones are designed to distribute the weight of the mound above

This architecture is deliberate. Without flat bearing surfaces, the structure would collapse under tonnes of earth.

Dolmens do not follow this logic.

Uprights are frequently pointed or angled
Contact points beneath the capstone are minimal
Load transfer is concentrated, not distributed

This makes dolmens mechanically unsuitable to be buried beneath an earthen mound.

In other words: if a dolmen had ever supported a long barrow mound, it would have failed.

Functional Design: Excarnation Sites

The internal geometry of dolmens instead matches a different, highly practical function: excarnation.

Key design features make sense only in this context:

Pointed uprights reduce access routes for scavengers and vermin
Raised capstones allow airflow while restricting entry
Angled stone surfaces permit bodily fluids to drain away naturally
Central, exposed positioning ensures visibility and access

These are not symbolic gestures. They are functional solutions to a biological process.

This design logic precisely mirrors what is observed in Phase I Stonehenge, where excarnation occurred within a controlled, elevated, chalk-lined environment.

Why the Confusion Persisted

The error arises because archaeology grouped monuments by appearance, not mechanics.

Superficially, dolmens and long barrows both involve stone chambers and human remains. Structurally and functionally, they are doing different jobs at different stages of mortuary practice.

Dolmens = exposure and defleshing
Long barrows = final deposition and ancestral consolidation

Once this distinction is made, a great deal of confusion disappears.

Dolmens were never meant to be buried.
They were meant to be open, elevated, draining, and inaccessible to animals.

That this has been missed for decades is not surprising — it requires thinking like an engineer, not just an archaeologist.

It is also essential to state that not every monument labelled “dolmen” qualifies as a true dolmen. Many sites grouped under that term lack point loading, lack minimal bearing surfaces, and were clearly designed to carry overburden.

They belong to a different structural and functional category.

Failure to separate these types has distorted interpretation for over a century.

Section 4 – The Landscape They Were Built For: Britain as a Water World

To understand long barrows properly, the most important question is not what they contained, but what landscape they were built into.

The answer is not the dry, stable countryside we see today.

It is a radically different early Holocene environment dominated by water.

Following the end of the last Ice Age, Britain experienced:

Elevated groundwater tables due to isostatic rebound
Vast meltwater discharge through river systems
Wide, braided rivers far exceeding modern floodplains
Extensive wetlands, shallow lakes, and inland estuaries
Seasonal and semi-permanent flooding of low ground

In this context, rivers were not features cutting through land.
They were the landscape itself.

Movement Followed Water

In a water-dominated environment, the logic of movement reverses:

Overland travel is slow, obstructed, and seasonal
Waterborne travel is faster, predictable, and load-bearing

Boats were not optional technology. They were infrastructure.

This has a critical archaeological implication that is almost always missed.

Navigation did not stop at sunset.

Chalk, Moonlight, and 24-Hour Navigation

The use of white chalk on long barrows is not simply about daylight visibility or ritual aesthetics.

Its most important function is lunar visibility.

Chalk reflects moonlight exceptionally well. Even under partial moon phases, a chalk-faced monument on elevated ground remains clearly visible against dark vegetation and water.

This enables:

Night-time navigation
Continuous 24-hour movement
Reliable travel aligned to lunar cycles and tides

In a water-based society, the ability to move under moonlight doubles transport capacity.

Long barrows were therefore not just markers in space.
They were markers in time.

Section 5 – Visibility, Moonlight, and Monument Permanence

In a shifting, flood-prone landscape, permanence is not achieved by enclosure or defence.

It is achieved by visibility.

Visibility as Function, Not Symbol

Long barrows are consistently positioned to:

Break skylines when viewed from low ground
Rise above mist, flood haze, and vegetation
Remain visible across open water and wetlands

When combined with chalk facing, this visibility operates:

In daylight
At twilight
Under moonlight

This transforms long barrows from passive monuments into active navigational infrastructure.

They are not destinations.
They are reference points.

The Stonehenge Connection

This is where long barrows connect directly to Stonehenge.

At Stonehenge, the Aubrey Holes and associated features demonstrate a system that tracks:

Lunar cycles
Tidal rhythms
Water height and movement

Stonehenge functions as a tidal and lunar calculator.

Stonehenge tells you when the water will move.
Long barrows tell you where to move under those conditions.

Together, they form a single, integrated system linking:

Time
Water
Movement
Memory

This is not symbolic astronomy.
It is operational landscape knowledge.

Section 6 – Death, the Voyage to the Afterlife, and Deep Continuity

A crucial fact must be stated plainly.

The idea of a voyage to the afterlife did not begin with Egypt or Mesopotamia.

It already existed — fully formed — during the fifth and sixth millennia BCE.

Death as Departure

Across later historical civilisations, the dead repeatedly:

Travel
Cross water
Board vessels
Are guided toward another realm

This appears in:

Egypt, with the solar barque
Mesopotamia, with river crossings into the underworld
Scandinavia, with ship burials
Classical Greece, with the ferryman and the river Styx

These traditions do not arise independently.

They inherit an older model.

Excarnation is often treated as a speculative ritual. In reality, it is a biological process with strict physical requirements.

Those requirements are well understood:

Elevation above ground
Free airflow around the body
Controlled drainage of fluids
Restricted access by scavengers
Visibility and supervision

True dolmens meet these requirements precisely.

The functional surface is the top of the capstone, not the space beneath it. Bodies placed on the slab benefit from airflow, natural runoff, and protection from ground scavengers. The angled stone surfaces observed in many examples are not incidental — they are engineered for drainage.

This same engineering logic is used today in cultures that practise excarnation. Modern exposure platforms, including Towers of Silence, employ identical principles of elevation, airflow, drainage, and exclusion.

This is not cultural continuity.
It is engineering convergence.

Different societies solving the same biological problem arrive at the same solution.

Megalithic Origins

The earliest megalithic societies embedded this idea into architecture:

Dolmens as excarnation and transformation sites
Long barrows as departure and consolidation monuments

Long barrows are not simple tombs.

They are departure structures, shaped like vessels, aligned with movement routes, and visible by moonlight.

The megalithic builders lived in a world where life followed water.
Death followed the same logic.

Section 7 – Distribution, Dates, and Proof of a Maritime Civilisation

The distribution of long barrows is not incidental.

It is diagnostic.

When dated correctly, long barrows cluster during the fifth and sixth millennia BCE in regions that were navigable by water.

They appear in:

Southern and eastern England
Wales
Ireland
Brittany and western France
The Low Countries
Northern Germany
Denmark
Southern Scandinavia

This is not a farming distribution.

It is a maritime distribution.

Traditional interpretations assume Neolithic farming communities as the builders of these monuments. That assumption has never been tested against the logistics of construction.

Dolmens and long barrows involve the movement of multi-ton stones. Without wheeled transport, roads, or draft animals, moving such loads over land is inefficient and dangerous.

Water transport changes the equation entirely.

Rivers, flooded plains, and estuaries allow heavy stones to be moved with minimal friction and maximal control. Any interpretation that ignores this logistical reality is incomplete.

This alone points away from a purely terrestrial farming model and toward an earlier, water-based system of movement.

(You can see how this is now perfectly set up for the dating evidence.)

Doggerland – The Missing Centre

At the centre of this system lay Doggerland.

During the fifth and sixth millennia BCE, Doggerland was:

A vast low-lying landmass
Dominated by rivers, wetlands, and coastlines
The primary connective zone between Britain and continental Europe

Doggerland is now submerged.

Because of this, the true density of long barrows and associated monuments is unknown.

What we see today is only the surviving outer rim of a much larger system.

This explains apparent gaps and inconsistencies on modern maps.

The centre has been erased.

Dates

Traditional interpretations place long barrows and dolmens within early Neolithic farming cultures. That assumption has been repeated so often it is rarely questioned. It should be.

When radiocarbon evidence is examined using modern calibration standards, a very different picture emerges.

Across multiple regions of Europe, the earliest secure radiocarbon dates associated with megalithic monuments consistently fall within the fifth, sixth, and in some cases seventh millennia BCE. These dates predate the arrival of established farming economies in several regions and sit firmly within the Mesolithic or Mesolithic–Neolithic transition.

This pattern is not local or anomalous. It is continental.

Using IntCal20 calibration and focusing specifically on Earliest Secure Dates from primary construction contexts, we see the following:

In France, secure dates extend back into the eighth millennium BCE.
In Germany, Denmark, Sweden, and Scotland, multiple sites cluster in the sixth and seventh millennia BCE.
In England and Ireland, earliest dates repeatedly fall well before the traditionally assigned Neolithic horizon.
In Portugal and Spain, early megalithic activity again precedes full agricultural adoption.

This is not compatible with a model in which megalith-building is driven by sedentary farming communities.

Why the Farming Model Fails Logistically

The Neolithic farming explanation also collapses under basic logistical analysis.

Dolmens and long barrows involve the movement and placement of multi-ton stones. In the absence of:

wheeled vehicles
roads
draft animals

Overland transport of such loads is inefficient, dangerous, and unnecessary.

By contrast, water transport solves the problem immediately.

Rivers, flooded plains, estuaries, and coastal routes allow heavy stones to be moved with minimal friction and maximum control. This is precisely the environment indicated by early Holocene hydrology and by the consistent placement of monuments near water routes and decision points.

Once water-based transport is acknowledged, the chronological evidence makes sense.

These monuments belong to a maritime society, not a terrestrial farming one.

Why Earlier Publications Are Now Outdated

Many earlier syntheses relied on:

uncalibrated BP dates treated as BCE
older calibration curves (IntCal09 or IntCal13)
Bayesian phase mid-points that reflect long-term use rather than initial construction

Against IntCal20, early Holocene dates frequently shift hundreds of years earlier. When Earliest Secure Dates are prioritised — short-lived samples from primary construction contexts — the apparent Neolithic boundary dissolves.

The issue is not reinterpretation.
It is better maths applied to better data.

The implication is unavoidable.

Megalithic construction begins earlier than traditionally claimed, in societies whose economies, mobility, and logistics were dominated by water.

Section 8 – What This Changes

This reinterpretation is not a minor adjustment.

It forces a structural reordering of prehistoric interpretation.

Long barrows are infrastructure that incorporates burial, not tombs with decoration
Hydrology becomes central, not optional
Regional consistency no longer requires myth or migration
Stonehenge and long barrows are revealed as components of the same system

One calculates time and tides.
The other anchors movement and memory.

Conclusion – Long Barrows Reframed

Long barrows were misunderstood because their world no longer exists.

They were built to:

Mark departure
Anchor memory
Enable movement within a water-dominated landscape

The voyage to the afterlife begins here, in the fifth and sixth millennia BCE, among societies whose lives were structured around water, tides, and moonlight.

Egypt and Mesopotamia did not invent this worldview.
They inherited and formalised it.

At the centre lay Doggerland, now beneath the sea.

Long barrows are not the beginning of monument building in Britain.
They are the surviving anchors of a mature maritime civilisation.

They were never mysterious.
They were misread.

Why Archaeology Missed This

The failure to distinguish dolmens from long barrows is not due to lack of excavation or data. It is a methodological blind spot.

Megalithic monuments have traditionally been classified by visual form and typology rather than by engineering function. Structures that look similar have been grouped together, even when their load mechanics, bearing surfaces, and structural capacities are fundamentally different.

Once monuments are categorised this way, interpretation becomes circular. If all are assumed to be burial monuments, then design features incompatible with burial are explained away as ritual variation rather than recognised as functional constraints.

This approach also assumes a dry, land-based Neolithic landscape and a farming economy capable of overland stone transport. The logistics of moving multi-ton stones without roads, wheels, or draft animals are rarely modelled in detail, and water-based transport is routinely sidelined.

As a result, three critical factors have been consistently underweighted:

structural mechanics
hydrology and transport logistics
taphonomic outcomes of exposure and reworking

When these factors are brought back into the analysis, long-standing assumptions no longer hold. Dolmens designed for point loading cannot be buried. Fragmentary remains no longer imply ritual choice alone. Monument placement near water and movement corridors becomes functional rather than symbolic.

In short, the issue is not a lack of evidence.
It is that the wrong questions have been asked of it.

Appendix – Earliest Secure Dates of Megalithic Monuments by Country (Summary)

Appendix — Earliest Secure Dates by Country (Top 5 per country)

(Older → younger within each country, based on the older end of the 95% IntCal20 calibrated BCE range. “RC Age” is the reported radiocarbon age in years BP.)

Denmark

Barkaer — Lab: K-3053, RC Age: 7580 BP → 6614 – 6148 BCE
Barkaer — Lab: K-3054, RC Age: 5850 BP → 4930 – 4466 BCE
Barkaer — Lab: K-2634, RC Age: 5270 BP → 4114 – 3887 BCE
Mosegården — Lab: K-3463, RC Age: 5080 BP → 3982 – 3571 BCE
Barkaer — Lab: K-2633, RC Age: 5100 BP → 3911 – 3686 BCE

England

Ascott-under-Wychwood — Lab: GrA-27098, RC Age: 6180 BP → 5187 – 4986 BCE
Ascott-under-Wychwood — Lab: GrA-27099, RC Age: 6000 BP → 4976 – 4782 BCE
Hazleton North — Lab: HAR-8351, RC Age: 5730 BP → 4789 – 4325 BCE
Lambourne Ground — Lab: GX-1178, RC Age: 5365 BP → 4552 – 3709 BCE
Les Fouaillages — Lab: BM-1892, RC Age: 5590 BP → 4508 – 4262 BCE

France

Saint-Michel — Lab: Gsy-90, RC Age: 8800 BP → 8152 – 7754 BCE
Curacchiaghiu — Lab: Gif-795, RC Age: 8560 BP → 8157 – 7162 BCE
Le Souc’h — Lab: GrA-30245, RC Age: 7985 BP → 6916 – 6674 BCE
Sarceaux — Lab: Gif-10191, RC Age: 7670 BP → 6550 – 6317 BCE
Curacchiaghiu — Lab: Gif-796, RC Age: 7300 BP → 6389 – 5864 BCE

Germany

Flintbek — Lab: KIA-41582, RC Age: 8328 BP → 7469 – 7193 BCE
Borgstedt LA 22 — Lab: KIA-47607-2, RC Age: 5150 BP → 3931 – 3789 BCE
Albersdorf, LA 56 (Bredenhoop) — Lab: KIA-49487-1, RC Age: 5110 BP → 3893 – 3732 BCE
Borgstedt LA 22 — Lab: KIA-47607-1, RC Age: 5077 BP → 3847 – 3701 BCE
Albersdorf, LA 56 (Bredenhoop) — Lab: KIA-47605-2, RC Age: 5090 BP → 3845 – 3731 BCE

Ireland

Ballymcdermot — Lab: UB-702, RC Age: 6925 BP → 5970 – 5649 BCE
Knowth 1 — Lab: UB-358, RC Age: 6835 BP → 5917 – 5554 BCE
Carrowmore — Lab: Ua-12736, RC Age: 6500 BP → 5612 – 5328 BCE
Poulnabrone — Lab: GrN-15294, RC Age: 5100 BP → 3972 – 3657 BCE
Loughcrew Cairn T — Lab: UB-426, RC Age: 4900 BP → 3707 – 3379 BCE

Malta (Central Mediterranean)

Skorba — Lab: (6140 BP) → 5230 – 4975 BCE
Tarxien — Lab: (4485 BP) → 3350 – 2920 BCE

Portugal

Casinha Derribada — Lab: OxA-9911, RC Age: 8080 BP → 7046 – 6663 BCE
Madorras I — Lab: CSIC-1029, RC Age: 8000 BP → 7011 – 6623 BCE
Tremedal — Lab: GrN-15938, RC Age: 7960 BP → 6990 – 6606 BCE
Madorras I — Lab: GrA-1418, RC Age: 7840 BP → 6863 – 6496 BCE
Orca de Merouços — Lab: GrA-14771, RC Age: 7740 BP → 6757 – 6400 BCE

Scotland

Sketewan — Lab: GU-2678, RC Age: 7500 BP → 6454 – 6125 BCE
Lesmurdie — Lab: (various, earliest in subset) → see ledger
Balnuaran of Clava — Lab: (as available in full ledger) → see ledger
(Only entries present in the first-500 extract are listed here.)

Spain

Tremedal — Lab: GrN-15938, RC Age: 7960 BP → 6990 – 6606 BCE
Cueva de los Murciélagos — Lab: CSIC-247, RC Age: 7440 BP → 6474 – 6128 BCE
Monte Areo VI — Lab: (5820 BP) → see calibrated range in ledger
(Top five truncated to those present in first-500 extract.)

Sweden

Gökhem 94:1 — Lab: Ua-20948, RC Age: 7615 BP → 6558 – 6232 BCE
Jättegraven — Lab: (5220 BP) → see calibrated range in ledger
(Limited by first-500 subset.)

Methods — How we calculated the BCE ranges (and why older books are off)

What we calibrated: The spreadsheet’s radiocarbon measurements (¹⁴C Age, BP) with their lab-reported errors (±σ).

Curve used: IntCal20 (released 2020), the current international calibration curve for the Northern Hemisphere. It supersedes IntCal13 (2013) and earlier curves.

Computation:

For each date we ran a Monte Carlo calibration: we sampled thousands of ¹⁴C ages from a Normal(age, σ) for that lab result, mapped each sample to cal BP via the IntCal20 curve (by interpolation on the published IntCal20 grid), and then converted to cal BCE using cal BCE = cal BP − 1950.
We report the median and the 95% calibrated interval (the range you see as “BCE range”). This captures the real-world uncertainty and the curve’s “wiggles.”
Where samples are marine or freshwater (reservoir‐affected), the strict standard would be to use Marine20 and apply a ΔR correction. Most entries here are terrestrial (charcoal, seeds, etc.); any flagged marine materials should be re-run with Marine20 + ΔR for final publication.

Why earlier publications disagree:

Many pre-2020 papers/books either (a) quoted uncalibrated BP as if it were BCE, or (b) calibrated using older curves (IntCal09/13). Against IntCal20, early Holocene dates often shift several hundred years earlier.
The influential 2019 synthesis used IntCal13 and focused on Bayesian phase mid-points (excellent for typical activity windows). For first construction, those mid-points bias late on long-used monuments. Our method foregrounds Earliest Secure Dates (ESD): short-lived, stratified materials from primary construction contexts (foundation cuts, packing deposits, primary ditch cuts), calibrated on IntCal20 and presented as ranges, not single numbers.

Bottom line:

BP is not BCE. Always calibrate.
Use IntCal20 (or later) and show ranges at 95%.
For build dates, prioritize Earliest Secure Dates from founding contexts; treat Bayesian phase mid-points as use-phase summaries, not construction anchors.

Full List of C14 dates

Schulz Paulsson, B. (2019). Radiocarbon dates and Bayesian modelling support the maritime diffusion model for megaliths in Europe. PNAS, 116(9): 3460–3465. Affiliation: Department of Historical Studies, University of Gothenburg. PubMed

Our Approach and Dates

Country	Site	Lab number	RC Age (BP)	BCE Range (95%)
Denmark	Barkaer	K-3053	7580	6614 - 6148
Denmark	Barkaer	K-3054	5850	4930 - 4466
Denmark	Barkaer	K-2634	5270	4114 - 3887
Denmark	Mosegården	K-3463	5080	3982 - 3571
Denmark	Barkaer	K-2633	5100	3911 - 3686
Denmark	Barkaer	K-2635	5090	3908 - 3670
England	Ascott-under-Wychwood	GrA-27098	6180	5187 - 4986
England	Ascott-under-Wychwood	GrA-27099	6000	4976 - 4782
England	Hazleton North	HAR-8351	5730	4789 - 4325
England	Lambourne Ground	GX-1178	5365	4552 - 3709
England	Les Fouaillages	BM-1892	5590	4508 - 4262
England	Ascott-under-Wychwood	BM-835	5198	4455 - 3391
England	Les Fouaillages	BM-1893	5510	4431 - 4154
England	Les Fouaillages	BM-1894	5280	4337 - 3693
England	Beckhampton Road	NPL-138	5200	4288 - 3554
England	La Hogue Bie	Beta-77360/ETH-13185	5410	4284 - 4056
England	La Hogue Bie	Beta-77359/ETH-13184	5400	4275 - 4038
England	Horslip	BM-180	5190	4266 - 3556
England	Hazleton North	OxA-912	5200	4266 - 3577
England	La Hogue Bie	Beta-57925/ETH-9972	5360	4223 - 3993
England	Ascott-under-Wychwood	OxA-12677	5353	4221 - 3983
England	La Hogue Bie	Beta-57926/ETH-9973	5245	4088 - 3859
England	Le Déhus	OxA-12542	5263	4079 - 3907
England	Ascott-under-Wychwood	OxA-12678	5246	4050 - 3899
England	La Hogue Bie	Beta-77361/ETH-13186	5210	4047 - 3817
England	Le Déhus	OxA-12540	5215	4028 - 3851
England	Le Déhus	OxA-21199	5222	4025 - 3861
England	Ascott-under-Wychwood	OxA-13318	5222	4016 - 3873
England	Le Déhus	OxA-12541	5194	4005 - 3826
England	Ascott-under-Wychwood	GrA-27102	5130	3937 - 3729
England	Ascott-under-Wychwood	GrA-23933	5105	3913 - 3704
England	Hazleton North	OxA-12969	5125	3909 - 3756
England	Ascott-under-Wychwood	GrA-27093	5100	3901 - 3694
England	Coldrum	OxA-16039	5101	3898 - 3716
England	Ascott-under-Wychwood	GrA-27094	5095	3897 - 3689
England	Ascott-under-Wychwood	GrA-27096	5095	3895 - 3686
England	Street House	BM-2061	5070	3879 - 3646
England	Coldrum	OxA-13718	5089	3873 - 3698
England	Coldrum	OxA-13734	5088	3862 - 3714
England	Coldrum	OxA-16040	5077	3858 - 3687
England	Coldrum	OxA-13733	5076	3857 - 3688
England	Coldrum	OxA-13743	5072	3838 - 3697
France	Curacchiaghiu	Gif-795	8560	8157 - 7162
France	Saint Michel	Gsy-90	8800	8152 - 7754
France	Le Souc´h	GrA-30245	7985	6916 - 6674
France	Sarceaux	Gif-10191	7670	6550 - 6317
France	Curacchiaghiu	Gif-796	7300	6389 - 5864
France	Hoëdic	OxA-6708	7165	6108 - 5907
France	Quélarn	Gif-5768	6990	6008 - 5713
France	L´Ubac	Ly-664	7060	6004 - 5840
France	L´Ubac	Ly-944	6920	5910 - 5680
France	Téviec	OxA-6665	6740	5753 - 5544
France	L´Ubac	Ly-1721	6700	5735 - 5509
France	Grotte de Puechmargues	Gif-446	6420	5667 - 4959
France	Hoëdic	OxA-6709	6645	5666 - 5468
France	Téviec	OxA-6702	6530	5578 - 5353
France	Téviec	OxA-6704	6515	5574 - 5325
France	Téviec	OxA-6703	6500	5558 - 5310
France	La Chaise	Ly-1797	6190	5549 - 4622
France	Téviec	OxA-6664	6510	5538 - 5353
France	Le Souc´h	Ly-2853	6440	5509 - 5237
France	Téviec	OxA-6663	6440	5491 - 5258
France	Dissignac	Gif-3823	6250	5487 - 4839
France	Dissignac	Gif-3822	6250	5484 - 4816
France	Vallon Carbonel	MC-1479	6200	5436 - 4767
France	Er Grah	A-8914	6305	5397 - 5077
France	Île Guennoc III	Gif-165	5800	5349 - 3926
France	Kercado	Sa-95	5840	5343 - 3999
France	Hoëdic	OxA-6706	6280	5340 - 5062
France	Le Souc´h	Ly-2855	6235	5249 - 5049
France	Saint Michel	Sa-96	5721	5239 - 3819
France	Tertre de Lomer	Gif-6027	6210	5236 - 5008
France	Table des Marchands	Ly-2508 (Poz.)	6210	5229 - 5005
France	Le Souc´h	Beta-161035	6090	5209 - 4757
France	Bougon/Chirons	Ly-966	5800	5179 - 4123
France	Hoëdic	OxA-6707	6080	5109 - 4836
France	Passy Sablonnière	Ly-6362/SacA-17072	6090	5060 - 4906
France	Passy Sablonnière	Ly-6364/SacA-17074	6050	5025 - 4852
France	Haut Mée	Ly-7662	5995	5024 - 4721
France	Haut Mée	Ly-7661	5995	5019 - 4721
France	Téviec	OxA-6701	6000	5012 - 4749
France	Bougon/Chirons	Ly-1700	5830	5005 - 4344
France	Haut Mée	Ly-356/AA-21673	5975	4993 - 4699
France	Er Grah	A-8913	5960	4987 - 4671
France	Barnenez	Gif-1309	5750	4945 - 4219
France	Goumoizère	GifA-97293	5940	4922 - 4691
France	Passy Richebourg	Ly-6356/SacA-17066	5960	4920 - 4741
France	Table des Marchands	Ly-13083	5930	4901 - 4696
France	Îlot de Roc´h Avel	Gif-5510	5800	4879 - 4409
France	Quélarn	Gif-5061	5760	4876 - 4317
France	Passy Richebourg	Ly-6363/SacA-17073	5910	4865 - 4682
France	Bougon/Chirons	Q-3234	5860	4863 - 4562
France	Lannec er Gadouer	AA-9241	5835	4846 - 4537
France	Table des Marchands	AA-20403	5835	4841 - 4526
France	Passy Sablonnière	Ly-6349/SacA-17059	5855	4827 - 4587
France	Table des Marchands	Ly-3015 (SacA-3319)	5770	4823 - 4401
France	Saint Michel	UB-6869	5854	4797 - 4619
France	Goumoizère	Ly-1048	5825	4796 - 4537
France	Lannec er Gadouer	AA-9240	5770	4795 - 4413
France	Passy Sablonnière	Ly-6350/SacA-17060	5845	4789 - 4598
France	Le Grée de Cojoux	Gif-5660	5660	4762 - 4183
France	Dissignac	GifA-92325	5720	4759 - 4326
France	Er Grah	A-8916	5760	4753 - 4430
France	Caune de Belesta	Ly-3302	5640	4732 - 4145
France	Goumoizère	OxA-9337/Ly-1125	5770	4723 - 4483
France	Saint Michel	GrA-20197	5780	4718 - 4506
France	Hoëdic	OxA-6710	5755	4712 - 4451
France	Sandun	Gif-7703	5660	4703 - 4235
France	Table des Marchands	Ly-5979	5585	4701 - 4076
France	Table des Marchands	Ly-3016(SacA3320)	5720	4692 - 4399
France	Passy Sablonnière	Ly-6355/SacA-17065	5730	4675 - 4441
France	Barnenez	Gif-1556	5550	4674 - 4010
France	Er Grah	Ly55-OxA	5650	4663 - 4239
France	Chenon	Ly-1105	5540	4654 - 3992
France	Le Grée de Cojoux	Gif-5456	5580	4654 - 4096
France	Passy Sablonnière	Ly-6348/SacA-17058	5730	4653 - 4465
France	Île Carn	Gif-414	5340	4652 - 3497
France	Grotte des Cranes	Gif-277	5200	4650 - 3197
France	Lannec er Gadouer	AA-10009	5700	4647 - 4388
France	Table des Marchands	Ly-13084	5715	4647 - 4434
France	Goumoizère	Beta-217481	5730	4647 - 4458
France	Bougon/Chirons	Ly-1699	5480	4645 - 3854
France	Ty Floc´h, St. Thois	Gif-5234	5580	4645 - 4096
France	Lannec er Gadouer	AA-20130	5640	4636 - 4270
France	Le Grée de Cojoux	Gif-5457	5550	4629 - 4059
France	Petit Mont	Gif-6844	5650	4625 - 4285
France	Téviec	OxA-6662	5680	4621 - 4377
France	Vierville/La Butte á Luzerne	OxA-11395	5690	4619 - 4406
France	Passy Richebourg	Ly-6360/SacA-17070	5690	4615 - 4401
France	Passy Richebourg	Ly-6357/SacA-17064	5695	4611 - 4417
France	Saint Michel	AA-42784	5665	4607 - 4347
France	Lannec er Gadouer	AA-29391	5660	4604 - 4345
France	Goumoizère	Ly-2494	5675	4604 - 4374
France	Haut Mée	Ly-7663	5650	4602 - 4318
France	Passy Richebourg	Ly-6359/SacA-17069	5675	4586 - 4395
France	Mestreville	GifA-92100	5550	4574 - 4096
France	Barnenez	Gif-1310	5450	4573 - 3849
France	Le Souc´h	Ly-2854	5650	4565 - 4357
France	Petit Mont	Gif-6846	5600	4562 - 4240
France	Passy Sablonnière	Ly-6353/SacA-17063	5655	4558 - 4365
France	Larcuste II	Gif-2826	5490	4550 - 3994
France	Balloy, Les Réaudins	Ly-5989	5615	4549 - 4282
France	Passy Richebourg	Ly-6354/SacA-17064	5635	4538 - 4350
France	Table des Marchands	AA-20404	5590	4537 - 4234
France	Goumoizère	OxA-9102/Ly-1047	5620	4536 - 4304
France	Passy Richebourg	Lyon-6361/SacA-17071	5635	4536 - 4338
France	Le Souc´h	Beta-161034	5630	4528 - 4344
France	Goumoizère	Ly-2488	5605	4527 - 4277
France	Goumoizère	Ly-2490	5610	4523 - 4298
France	Balloy, Les Réaudins	Ly-5886	5610	4515 - 4308
France	Les Erves	Ly-3099	5580	4497 - 4261
France	Goumoizère	Ly-2491	5590	4495 - 4269
France	Île Carn	Gif-1362	5390	4490 - 3791
France	Goumoizère	Beta-217483	5590	4483 - 4294
France	Beg-an-Dorchem	GifA-923372	5490	4469 - 4051
France	La Hoguette	Ly-131	5560	4463 - 4223
France	Goumoizère	Ly-2489	5555	4460 - 4232
France	Goumoizère	Beta-217475	5570	4458 - 4266
France	Balloy, Les Réaudins	Ly-5885	5500	4447 - 4101
France	Passy Sablonnière	Ly-7808	5545	4447 - 4211
France	Balloy, Les Réaudins	Ly-5549	5532	4435 - 4199
France	Prajou Menhir	Gif-767	5330	4410 - 3720
France	Goumoizère	Ly-2492	5520	4410 - 4190
France	Goumoizère	Beta-217474	5530	4410 - 4220
France	Table des Marchands	Ly-3013 (SacA-3317)	5480	4409 - 4117
France	Er Grah	A-8915	5495	4408 - 4133
France	Balloy, Les Réaudins	Ly-5587	5500	4390 - 4157
France	Table des Marchands	Ly-12314	5500	4384 - 4172
France	Péré, tumulus C	OxA-10249	5500	4383 - 4172
France	Changé, (Saint Piat)	Gif A- 92352	5470	4366 - 4113
France	Monte Revincu, Dolmen de Casa di l´Urca	Poz-25355	5490	4360 - 4169
France	Table des Marchands	A-8857	5440	4351 - 4066
France	Lannec er Gadouer	AA-8819	5445	4351 - 4071
France	Péré, tumulus C	OxA-10204	5470	4347 - 4136
France	Table des Marchands	Ly-3017 (SacA-3321)	5440	4342 - 4068
France	Table des Marchands	Ly-3014(SacA3318)	5430	4338 - 4054
France	Péré, tumulus C	OxA-10258	5465	4338 - 4132
France	Bougon/Chirons	OxA-9183	5415	4334 - 4026
France	Monte Revincu, Casa di L´Urcu	Ly-9713	5405	4331 - 4006
France	Goumoizère	Beta-217477	5460	4323 - 4134
France	La Hoguette	Ly-421	5160	4319 - 3411
France	La Motte des Justices	Gif-8292	5340	4318 - 3854
France	Table des Marchands	A-8855	5395	4318 - 3973
France	Monte Revincu, Dolmen de Casa di l´Urca	Poz-25356	5450	4316 - 4124
France	Péré, tumulus C	OxA-10248	5440	4311 - 4103
France	Monte Revincu, Dolmen de Casa di l´Urca	Poz-25357	5440	4304 - 4111
France	Vierville/La Butte á Luzerne	OxA-11396	5430	4303 - 4087
France	Goumoizère	Beta-217479	5440	4301 - 4114
France	Vierville/La Butte á Luzerne	OxA-12980	5448	4301 - 4128
France	Monte Revincu, secteur de la Cima de Suarella	Ly-8396	5405	4300 - 4033
France	Goumoizère	Beta-217478	5440	4296 - 4111
France	Er Grah	Gif-7693	5370	4288 - 3958
France	Passy Richebourg	Ly-6358/SacA-17068	5425	4283 - 4096
France	Table des Marchands	Ly-2509 (Poz.)	5415	4277 - 4069
France	Monte Revincu, Dolmen de Cellucia	Poz-13801	5410	4261 - 4076
France	Péré, tumulus C	OxA-10205	5395	4254 - 4048
France	L´Ubac	Ly-794	5220	4251 - 3644
France	Champ Châlon, Monument B1	OxA-9097	5365	4250 - 3984
France	Bougon/Chirons	OxA-9106/Ly-1051	5365	4236 - 3995
France	Monte Revincu	Ly-8395	5355	4232 - 3981
France	Îlot de Roc´h Avel	GrN-1966	5340	4225 - 3933
France	Goumoizère	Ly-2493	5360	4223 - 3998
France	Vierville/La Butte á Luzerne	OxA-12896	5375	4220 - 4036
France	Najac	Erl 12289	5354	4217 - 3983
France	Péré, tumulus C	OxA-10246	5360	4217 - 4007
France	Monte Revincu, Casa di L´Urcu	Ly-13092	5355	4216 - 3985
France	Camp del Ginébre	Ly-226	5355	4214 - 3996
France	Balloy, Les Réaudins	Ly-6406	5305	4212 - 3870
France	Table des Marchands	A-8856	5325	4205 - 3925
France	Goumoizère	Beta-217476	5360	4200 - 4019
France	Ty Floc´h, St. Thois	Ly-199	5270	4192 - 3814
France	Goumoizère	Beta-217482	5350	4191 - 4001
France	Îlot de Roc´h Avel	GifA-92374	5260	4186 - 3785
France	Table des Marchands	Ly-8 (OxA)	5260	4184 - 3803
France	Vierville/La Butte á Luzerne	OxA-13019	5349	4173 - 4016
France	Balloy, Les Réaudins	Ly-5547	5315	4171 - 3936
France	Colombiers-sur-Seulles	Gif-1917	5150	4164 - 3555
France	Vierville/La Butte á Luzerne	OxA-13018	5339	4162 - 4003
France	Bougon/Chirons	Q-3233	5280	4152 - 3883
France	Péré, tumulus C	OxA-10247	5295	4141 - 3924
France	Camp de la Vergentière	Ly-3055	5300	4141 - 3938
France	Er Grah	Gif-7691	5250	4136 - 3808
France	Bougon/Chirons	Q-3218	5230	4132 - 3796
France	Île Carn	GrN-1968	5230	4129 - 3779
France	Bougon/Chirons	Q-3235	5250	4129 - 3833
France	Castello d'Araggio, C-Ar-4	Gif-1000	5130	4128 - 3535
France	Îlot de Roc´h Avel	GrN-1968	5230	4128 - 3780
France	Table des Marchands	A-8854	5175	4123 - 3658
France	Petit Mont	Gif-7307	5230	4123 - 3788
France	Najac	Erl-12291	5268	4117 - 3881
France	Barnenez	Gif-1116	5100	4114 - 3480
France	Najac	Erl 12290	5265	4112 - 3881
France	Er Grah	Gif-7592	5260	4104 - 3877
France	Neuvy-en-Dunois	no information	5250	4096 - 3864
France	Île Guennoc III	Gif-1870	5075	4093 - 3421
France	La Pierre Tourneresse	Ly-11310	5235	4087 - 3839
France	Liscuis I	Gif-3099	5140	4074 - 3613
France	Changé, (Saint Piat)	Gif A- 91091	5230	4069 - 3838
France	Bougon/Chirons	Q-3217	5145	4066 - 3659
France	Lannec er Gadouer	AA-29390	5210	4064 - 3806
France	Table des Marchands	LGQ-558	5220	4060 - 3828
France	Bougon/Chirons	Q-3215	5195	4039 - 3784
France	L´île Bono	Gsy-64	5195	4033 - 3796
France	La Pierre Tourneresse	Ly-11312	5190	4023 - 3794
France	Bougon/Chirons	Q-3232	5190	4022 - 3786
France	Table des Marchands	Ly-12312	5170	3974 - 3788
France	Camp del Ginébre	Ly-267	5100	3948 - 3661
France	Petit Mont	Gif-8287	5130	3931 - 3744
France	Le Souc´h	CIRAM AA-022	5105	3925 - 3690
France	Bougon/Chirons	Q-3214	5085	3921 - 3640
France	Montou	Ly-4661?	5095	3913 - 3681
France	Hoëdic	OxA-6705	5080	3902 - 3653
France	Champ Châlon, Monument B2	OxA-9595	5090	3881 - 3696
France	Port Blanc	OxA-10615	5070	3879 - 3646
Germany	Flintbek	KIA-41582	8328	7469 - 7193
Germany	Borgstedt LA 22	KIA-47607-2	5150	3931 - 3789
Germany	Albersdorf: LA 56: Bredenhoop	KIA-49487-1	5110	3893 - 3732
Germany	Borgstedt LA 22	KIA-47607-1	5077	3847 - 3701
Germany	Albersdorf: LA 56: Bredenhoop	KIA-47605-2	5090	3845 - 3731
Ireland	Ballymcdermot	UB-702	6925	5970 - 5649
Ireland	Knowth 1	UB-358	6835	5917 - 5554
Ireland	Carrowmore	Ua-12736	6500	5576 - 5289
Ireland	Carrowmore	Lu-1840	5750	4772 - 4380
Ireland	Slieve Gullion	UB-179	5215	4405 - 3469
Ireland	Carrowmore	Ua-16970	5320	4177 - 3944
Ireland	Carrowmore	Lu-1441	5240	4155 - 3782
Ireland	Carrowmore	Ua-16974	5230	4137 - 3761
Ireland	Primrose Grange	Ua-16967	5230	4135 - 3780
Ireland	Carrowmore	Ua-13382	5180	4103 - 3677
Ireland	Carrowmore	Ua-16110	5255	4099 - 3865
Ireland	Dooey´s Cairn	UB-2030	5150	4062 - 3649
Ireland	Primrose Grange	Ua-16968	5145	4019 - 3679
Ireland	Primrose Grange	Ua-11582	5140	3991 - 3699
Ireland	Poulnabrone	OxA-1906	5100	3985 - 3618
Italy	Contraguda	OZC-966	5423	4299 - 4073
Italy	Contraguda	OZC-965	5369	4237 - 4001
Italy	Contraguda	GRA-13478	5310	4174 - 3938
Italy	Sa ´Ucca de su Tintirriolu	R-884	5090	3906 - 3675
Italy	San Benedetto	AA-78327	5078	3900 - 3638
Italy	Contraguda	GRA-Beta-149261	5070	3880 - 3646
Maltese Archipelago	Skorba	BM-378	6140	5478 - 4587
Maltese Archipelago	Skorba	BM-216	5760	4957 - 4187
Maltese Archipelago	Skorba	BM-142	5240	4316 - 3609
Maltese Archipelago	Brochtorff Circle	OxA-5038	5330	4303 - 3831
Maltese Archipelago	Brochtorff Circle	OxA-3572	5380	4292 - 3971
Maltese Archipelago	Skorba	BM-148	5175	4231 - 3525
Maltese Archipelago	Skorba	BM-147	5140	4203 - 3505
Maltese Archipelago	Brochtorff Circle	OxA-3568	5170	4035 - 3734
Maltese Archipelago	Brochtorff Circle	OxA-5039	5170	4022 - 3737
Poland	Lupawa	Bln-1814	6060	5136 - 4761
Poland	Lupawa	Bln-1593	5730	4658 - 4445
Poland	Sarnowo	GrN-5035	5570	4505 - 4219
Poland	Wietrzychowice	Lod-60	5170	4313 - 3469
Poland	Krusza Zamkova	Gd-309	5140	4173 - 3493
Portugal	Orquinha dos Juncais	GrA-17166	8750	8144 - 7673
Portugal	Casinha Derribada	OxA-9911	8080	7223 - 6681
Portugal	Madorras I	GrA-1418	7840	7064 - 6312
Portugal	Madorras I	CSIC-1029	8000	6923 - 6710
Portugal	Tremedal	GrN-15938	7960	6920 - 6602
Portugal	Orca de Merouços	GrA-14771	7740	6599 - 6412
Portugal	Cabeçuda	ICEN-978	7660	6526 - 6330
Portugal	Cabeço da Arruda (Muge), Ribatejo	Beta-12745	7550	6500 - 6165
Portugal	Cabeço da Amoreira (Muge), Ribatejo	TO-11819R	7300	6258 - 5990
Portugal	Arapouco	Sac-1560	7200	6245 - 5821
Portugal	Moita do Sebastião (Muge), Ribatejo	TO-131	7240	6185 - 5950
Portugal	Moita do Sebastião (Muge), Ribatejo	TO-133	7200	6152 - 5923
Portugal	Moita do Sebastião (Muge), Ribatejo	TO-134	7160	6143 - 5868
Portugal	Moita do Sebastião (Muge), Ribatejo	TO-132	7180	6139 - 5910
Portugal	Cabeço das Amoreiras, Alentejo	Beta-125110	7230	6130 - 5995
Portugal	Cova da Onça (Magos), Ribatejo	Beta-127448	7140	6052 - 5923
Portugal	Moita do Sebastião (Muge), Ribatejo	Beta-127449	7120	6034 - 5909
Portugal	Cabeço da Arruda (Muge), Ribatejo	TO-10216	7040	6002 - 5804
Portugal	Châ de Carvahal 1	OxA-2128	7030	5980 - 5817
Portugal	Cabeço da Arruda (Muge), Ribatejo	TO-359	6960	5955 - 5718
Portugal	Cabeço da Arruda (Muge), Ribatejo	TO-360	6990	5943 - 5775
Portugal	Cabeço da Arruda (Muge), Ribatejo	TO-354	6970	5931 - 5767
Portugal	Châ da Parada 3	Gif-8290	6910	5915 - 5682
Portugal	Moita do Sebastião (Muge), Ribatejo	TO-135	6810	5830 - 5591
Portugal	Cabeço do Pez, Alentejo	Sac-1558	6740	5814 - 5491
Portugal	Cabeço da Amoreira (Muge), Ribatejo	Beta-127450	6850	5809 - 5678
Portugal	Cabeço da Arruda (Muge), Ribatejo	TO-355	6780	5768 - 5600
Portugal	Cabeço do Pez, Alentejo	Beta-125109	6760	5735 - 5603
Portugal	Carvahal	GrA-5427	6730	5723 - 5562
Portugal	Cabras	CSIC-1056	6570	5657 - 5333
Portugal	Cabeço da Arruda (Muge), Ribatejo	TO-10217	6620	5646 - 5451
Portugal	Cabeço da Amoreira (Muge), Ribatejo	TO-10225	6550	5606 - 5358
Portugal	Castelhanas	ICEN-1264	6360	5513 - 5038
Portugal	Samouqueira 1	TO-130	6370	5454 - 5142
Portugal	Outeiro de Ante 1	Gif-8291	6310	5419 - 5049
Portugal	Cabeço da Arruda (Muge), Ribatejo	TO-356	6360	5402 - 5180
Portugal	Correio- Mór	Sac-1717	6330	5398 - 5121
Portugal	Châ de Carvahal 1	OxA-1850	6340	5380 - 5159
Portugal	Cabras	CSIC-1055	6160	5227 - 4911
Portugal	Figueira Branca	ICEN-823 (double lab.code)	6210	5227 - 5004
Portugal	Châ de Carvahal 1	OxA-1848	6150	5162 - 4941
Portugal	Cabritos 3	Gif-7020	6100	5157 - 4843
Portugal	Châ da Parada 4	ICEN-170	5530	5021 - 3622
Portugal	Menhir de Meada	UtC-4452	6022	4995 - 4813
Portugal	Areita 1	Sac-1514	5970	4981 - 4714
Portugal	Outeiro de Ante 2	GaK-10937	5920	4901 - 4665
Portugal	Châ de Carvahal 1	UGRA-355	5860	4854 - 4577
Portugal	Outeiro de Ante 3	Gif-4857	5780	4807 - 4436
Portugal	Areita 1	Sac-1508	5830	4787 - 4561
Portugal	Alcalar 7	Beta-180978	5810	4777 - 4534
Portugal	Monte Maninho	GrN-15569	5805	4747 - 4559
Portugal	Gruta dos Escoral	OxA-4444	5560	4735 - 3978
Portugal	Monte Maninho	CSIC-755	5680	4685 - 4307
Portugal	Monte da Olheira	UGRA-287	5630	4649 - 4226
Portugal	Castelo Belinho	Beta-199913	5720	4637 - 4454
Portugal	Alcalar 7	Beta-180981	5690	4600 - 4411
Portugal	Areita 1	CSIC-1327	5699	4595 - 4446
Portugal	Outeiro de Ante 3	Gif-4858	5540	4565 - 4120
Portugal	Alcalar 7	Sac-1794	5640	4562 - 4332
Portugal	Areita 1	CSIC-1326	5629	4525 - 4348
Portugal	Outeiro de Gregos 2	KN-2768	5500	4446 - 4115
Portugal	Castelo Belinho	Beta-199912	5500	4373 - 4183
Portugal	Châ da Parada 4	ICEN-162	5470	4347 - 4137
Portugal	Chã de Carvahal 1	OxA-1849	5450	4332 - 4100
Portugal	Portela do Pau 2	CSIC-1121	5435	4307 - 4094
Portugal	Portela do Pau 1	CSIC-1003	5440	4292 - 4123
Portugal	Châ da Parada 4	ICEN-169	5420	4272 - 4083
Portugal	Monte da Olheira	GrN-15331	5400	4251 - 4064
Portugal	Lameira de Cima 2	OxA-5102	5360	4244 - 3978
Portugal	Antelas	OxA-5496	5330	4185 - 3952
Portugal	Furnas 2	CSIC-775	5270	4169 - 3836
Portugal	Châ da Parada 4	ICEN-890	5240	4168 - 3765
Portugal	Furnas 1	CSIC-777	5270	4164 - 3836
Portugal	Cabras	ICEN-1265	5290	4148 - 3908
Portugal	Antelas	OxA-5497	5295	4147 - 3914
Portugal	Meninas do Crastro 2	CSIC-659a	5260	4135 - 3850
Portugal	Outeiro de Gregos 3	KN-2766	5230	4128 - 3783
Portugal	Châ da Parada 4	ICEN-891	5240	4121 - 3805
Portugal	Meninas do Crastro 2	CSIC-657	5260	4112 - 3878
Portugal	Madorras I	CSIC-1030	5280	4108 - 3922
Portugal	Meninas do Crastro 2	CSIC-656	5260	4106 - 3881
Portugal	Meninas do Crastro 2	CSIC-658	5260	4104 - 3875
Portugal	Cabras	ICEN-1267	5220	4082 - 3796
Portugal	Cabras	ICEN-1266	5220	4076 - 3804
Portugal	Outeiro de Gregos 3	KN-2765	5200	4074 - 3757
Portugal	Mina do Simão	CSIC-717	5130	4057 - 3632
Portugal	Areita 1	GrA-18518	5170	4027 - 3731
Portugal	Cave de Cadaval	ICEN-464	5160	3985 - 3755
Portugal	Monte da Olheira	GrN-15330	5195	3970 - 3853
Portugal	Picoto da Vasco	CSIC-1221	5160	3968 - 3774
Portugal	Senhora do Monte 3	ICEN-1200	5100	3961 - 3640
Portugal	Carapito 1	OxA-3733	5125	3944 - 3713
Portugal	Picoto da Vasco	GrN-22443	5140	3944 - 3753
Portugal	Picoto da Vasco	GrN-22817	5100	3936 - 3655
Portugal	Senhora do Monte 3	GrN-20791	5130	3929 - 3743
Portugal	Carapito 1	TO-3336	5120	3917 - 3731
Portugal	Mamoa do Castelo 1	CSIC-1818	5112	3901 - 3730
Portugal	Portela do Pau 2	CSIC-1120	5131	3901 - 3770
Portugal	Picoto da Vasco	CSIC-1328	5124	3900 - 3758
Portugal	Portela do Pau 2	CSIC-1119	5087	3860 - 3713
Scotland	Sketewan	GU-2678	7500	6421 - 6163
Scotland	Balnuaran of Clava	AA-21260	6670	5731 - 5446
Scotland	Balnuaran of Clava	AA-21255	6410	5502 - 5171
Scotland	Biggar Common	GU-2987	6300	5490 - 4940
Scotland	Biggar Common	GU-2988	6080	5107 - 4839
Scotland	Boghead	SRR-690	6006	5000 - 4772
Scotland	Kilpatrick	GU-1561	5870	4899 - 4555
Scotland	Cleaven Dyke	GU-3912	5550	4652 - 4034
Scotland	Cleaven Dyke	GU-3911	5500	4570 - 4004
Scotland	Dalladies	I-6113	5190	4147 - 3670
Scotland	Biggar Common	GU-2985	5250	4095 - 3864
Scotland	Monamore	Q-675	5110	4078 - 3556
Scotland	Maes Howe	SRR-791	5090	4036 - 3546
Scotland	Biggar Common	GU-2986	5150	4025 - 3691
Spain	Cuevo de los Murciélagos	CSIC-247	7440	6409 - 6080
Spain	Valdemuriel 2	GrN-14494	6565	5582 - 5426
Spain	Chan de Prado 6	GrN-19620	6575	5572 - 5455
Spain	Larrarte	I-14781	5810	5330 - 3972
Spain	Font de la Vena	UBAR-61	6190	5215 - 4987
Spain	Cova de I´Avellaner	GaK-12933	5920	5200 - 4358
Spain	Coto dos Mouros	CAMS-83116	6050	5186 - 4673
Spain	Cuevo de los Murciélagos	CSIC-1133	6086	5082 - 4880
Spain	Chan da Cruz 1	GaK-11395	5890	5034 - 4468
Spain	Alto da Barreira	CSIC-1039	6030	4983 - 4846
Spain	Cerro Virtud	Beta-90885	5920	4945 - 4619
Spain	Cerro Virtud	OxA-6715	5895	4886 - 4626
Spain	Cerro Virtud	Beta-101425	5860	4877 - 4547
Spain	Cerro Virtud	OxA-6580	5840	4873 - 4492
Spain	Castillejo	Beta-132917	5710	4872 - 4186
Spain	Azutan	Ly-4578	5750	4860 - 4277
Spain	Cuevo de los Murciélagos	CSIC-1134	5900	4853 - 4669
Spain	El Padró II	UBAR-115	5870	4847 - 4609
Spain	Monte Areo VI	GrN-19123	5820	4833 - 4502
Spain	Cuevo de los Murciélagos	CSIC-1132	5861	4823 - 4602
Spain	Cova de I´Avellaner	UBAR-109	5830	4793 - 4560
Spain	Larratbi		5810	4772 - 4539
Spain	Font de la Vena	UBAR-60	5780	4738 - 4497
Spain	Cerro Virtud	OxA-6713	5765	4728 - 4472
Spain	Valdemuriel 1	Grn-14128	5670	4721 - 4218
Spain	El Padró II	UBAR-114	5770	4716 - 4492
Spain	Cerro Virtud	Beta-90884	5660	4666 - 4287
Spain	Joaninha	Sac-1380	5400	4644 - 3674
Spain	Catasol 2	CSIC-985	5680	4579 - 4412
Spain	Campo del Hockey	CNA-360	5650	4555 - 4362
Spain	Hayas I	GrN-21232	5490	4549 - 3959
Spain	Boeriza 2	Ua-3228	5500	4521 - 4039
Spain	El Padró II	UBAR-113	5600	4513 - 4280
Spain	El Padró II	UBAR-116	5580	4495 - 4250
Spain	Mámoa do Monte: dos Marxos	CAMS-77925	5540	4491 - 4172
Spain	Monte Areo V	GrN-22026	5470	4458 - 4026
Spain	Bòbila Madurell	UBAR-401	5540	4449 - 4210
Spain	Trikuaizti I	I-14099	5300	4385 - 3682
Spain	Dolmen d`Arreganyats	UGRA-148	5400	4382 - 3912
Spain	Cuevo de los Murciélagos	CSIC-246	5400	4346 - 3973
Spain	Catasol 2	CSIC-984	5470	4325 - 4159
Spain	Fuentepecina	GrN-16073	5270	4320 - 3675
Spain	La Cabana 2	Ua-3231	5405	4312 - 4015
Spain	Els Vilars	UBAR-554	5340	4300 - 3875
Spain	Cotogrande 1	GrN-17698	5329	4276 - 3886
Spain	Monte Areo XII	UtC-7218	5404	4259 - 4066
Spain	Mámoa do Monte: dos Marxos	CAMS-77924	5330	4257 - 3885
Spain	Igartza W	I-18214	5270	4245 - 3768
Spain	Els Vilars	UBAR-666	5280	4231 - 3807
Spain	Alberite	Beta-80602	5320	4229 - 3904
Spain	Fuentepecina	GrN-18669	5375	4229 - 4023
Spain	Los Llanos 1	I-15168	5190	4225 - 3558
Spain	Monte Areo XII	UtC-7217	5368	4222 - 4017
Spain	Monte Areo XII	UtC-7219	5368	4213 - 4019
Spain	La Mina	GrN-14951	5100	4193 - 3420
Spain	Monte Areo V	GrN-22027	5330	4190 - 3953
Spain	Cova del Lladres	UBAR-63	5330	4190 - 3955
Spain	Dolmen de Tires Llargues	GaK-12162	5090	4180 - 3400
Spain	As Rozas 1	CSIC-11189	5150	4177 - 3526
Spain	Bòbila Madurell	UBAR-442	5310	4168 - 3936
Spain	Ventin 4	CSIC-1108	5320	4153 - 3971
Spain	Alberite	Beta-80600	5110	4128 - 3471
Spain	Ciella	GrN-12121	5290	4117 - 3935
Spain	La Cabaña	GrN-18670	5240	4116 - 3816
Spain	Monte Areo XII	UtC-7220	5284	4115 - 3918
Spain	Rebolledo	GrN-19569	5305	4114 - 3975
Spain	Fuentepecina	GrN-18667	5170	4096 - 3652
Spain	Velilla 2	GrN-16296	5250	4093 - 3861
Spain	Boeriza 2	Ua-3229	5200	4091 - 3752
Spain	Sierra Plana de la Borbolla 24	OxA-6914	5230	4071 - 3838
Spain	Monte Areo XII	CSIC-1379	5261	4065 - 3919
Spain	Velilla 3	GrN-16297	5200	4049 - 3788
Spain	Chan da Cruz 1	CSIC-642	5210	4043 - 3811
Spain	Morceo	GrN-12994	5150	4003 - 3719
Spain	La Llaguna A	GrN-18283	5140	3991 - 3708
Spain	Pena Ovieda I	GrN-18782	5195	3972 - 3856
Spain	Monte Areo XII	CSIC-1378	5176	3963 - 3822
Spain	La Llaguna D	GrN-16648	5110	3951 - 3672
Spain	El Miradero	GrN-12101	5155	3951 - 3782
Spain	La Llaguna A	GrN-18282	5175	3946 - 3828
Spain	La Llaguna D	GrN-1664	5135	3934 - 3747
Spain	Els garrofers del torrent de Sta. Maria	UBAR-100	5100	3915 - 3685
Spain	Monte Areo XII	CSIC-1380	5133	3909 - 3774
Spain	El Miradero	GrN-12100	5115	3898 - 3736
Spain	Rebolledo	GrN-19567	5075	3866 - 3679
Spain	La Xorenga	CSIC-1381	5080	3845 - 3704
Sweden	Gökhem 94: 1	Ua-20948	7615	6472 - 6306
Sweden	Lyse 7	St-4567	5545	4443 - 4212
Sweden	Uglhöj	K-6977	5220	4157 - 3742
Sweden	Jättegraven	Ua-2788	5220	4053 - 3828
Sweden	Odarslöv	LuS-7145	5115	3936 - 3703
Sweden	Örnakulla	Ua-13606	5095	3905 - 3676

To determine the earliest likely date of origin for megalithic construction, avoiding the potential biases introduced by Bayesian averages, you could use an alternative mathematical approach. Here are some potential methods:

1. Minimum Date Selection

Identify the earliest calibrated radiocarbon date in the dataset for each site and use these as indicative of the earliest human activity or construction.

2. Terminus Ante Quem Approach

Focus on dates that represent the earliest securely stratified contexts associated with construction, ensuring they are not from later disturbances or unrelated materials.

3. Cluster Analysis

Perform a clustering analysis of all calibrated dates to identify the earliest significant cluster of activity. This can help filter out outliers and provide a more accurate picture of early construction activity.

4. Monte Carlo Simulation

Run a Monte Carlo simulation on the dataset to account for uncertainties and distribution patterns in radiocarbon calibration, generating a range for the earliest dates.

5. Probability Density Function Peaks

Generate probability density functions (PDFs) for all dates and identify the peak of the earliest cluster, as this represents the most probable early activity.

6. Stratigraphic and Contextual Filtering

Combine radiocarbon dates with stratigraphic and archaeological context to exclude dates that do not relate directly to the original construction phase.

(Maritime Diffusion Model for Megaliths in Europe)

This appendix is not supplementary colour. It is the chronological backbone of the argument.

By presenting calibrated ranges at 95% confidence using IntCal20, and by explicitly separating construction signals from later use-phases, it resolves a long-standing distortion in the literature.

The conclusion follows directly from the data.

Appendix – Case Study: Arthur’s Stone and Controlled Excarnation Landscapes

Arthur’s Stone, Herefordshire

Recent excavation and reassessment at Arthur’s Stone has fundamentally altered how this monument should be understood.

Arthur’s Stone has traditionally been classified as a Neolithic chambered tomb. That interpretation was based largely on its visible stone structure and the long-standing assumption that all such monuments functioned primarily as burial chambers.

However, extended excavation beyond the stone footprint revealed evidence that does not fit a simple tomb model.

Key Findings from Excavation

The most significant discoveries were:

Evidence of an earlier turf mound predating the visible stone structure
A surrounding timber palisade, identified through post-hole traces located well beyond the stones themselves
Indications of controlled access and defined perimeter, rather than open deposition
A sequence suggesting earlier activity phases prior to the construction of the final stone arrangement

Critically, the palisade was not attached to the stone structure and would have left no visible trace without wide-area excavation. This is precisely the kind of feature that would be missed if investigation were limited to beneath or immediately around the stones.

Why the Palisade Matters

A palisade is not required for a sealed burial monument.
It is, however, entirely logical for an excarnation site.

A timber enclosure provides:

Control of large scavengers
Regulation of human access
Definition of a managed operational space
Preservation of airflow and exposure

This combination is unnecessary for interment, but essential for exposure-based mortuary practice.

Arthur’s Stone therefore demonstrates that at least some monuments traditionally labelled as tombs were instead controlled exposure environments, later monumentalised in stone.

Linking Arthur’s Stone to Stonehenge Phase 1

This pattern is not isolated.

At Stonehenge Phase 1, excavation has revealed:

Fragmentary human remains consistent with excarnation rather than primary burial
A surrounding perimeter structure, interpreted as an early enclosure or palisade
Stone holes (including the Q and R series) that are not burial cuts and not load-bearing foundations

Together, these elements define a managed excarnation complex, not a cemetery.

The semi-circular arrangement of early stone holes, oriented toward lunar movement, suggests that excarnation at Stonehenge was not only controlled spatially but also regulated temporally, potentially tied to lunar visibility and cycles.

Functional Convergence, Not Coincidence

Arthur’s Stone and Stonehenge Phase 1 share a consistent operational logic:

Exposure rather than interment
Perimeter control via timber structures
Fragmentary remains resulting from secondary processes
Monumentalisation following earlier, less permanent phases

The materials differ — timber, turf, and stone — but the problem being solved is the same, and so is the solution.

This convergence strongly suggests that dolmens, early stone platforms, and palisaded enclosures belong to a single excarnation tradition, expressed differently according to landscape, material availability, and later reuse.

Why This Has Been Missed

In both cases, recognition of excarnation depended on excavation beyond the monument core. Where archaeology assumes “tomb” in advance, excavation strategy is directed downward rather than outward, and ephemeral perimeter features are systematically overlooked.

Arthur’s Stone demonstrates that absence of palisades at other sites cannot be treated as evidence of absence. It is more accurately evidence of methodological constraint.

Implications

Taken together, Arthur’s Stone and Stonehenge Phase 1 show that:

Excarnation sites were structured, enclosed, and controlled
Timber palisades were a standard solution, even though they rarely survive
Stone monuments often represent later monumentalisation of earlier practices
Fragmentary human remains are an expected outcome of process, not ritual anomaly

This case study therefore provides a critical anchor point for reinterpreting dolmens and early megalithic sites as part of a coherent, engineered excarnation system rather than isolated burial monuments.

PodCast

Author’s Biography

Robert John Langdon, a polymathic luminary, emerges as a writer, historian, and eminent specialist in LiDAR Landscape Archaeology.

His intellectual voyage has interwoven with stints as an astute scrutineer for governmental realms and grand corporate bastions, a tapestry spanning British Telecommunications, Cable and Wireless, British Gas, and the esteemed University of London.

A decade hence, Robert’s transition into retirement unfurled a chapter of insatiable curiosity. This phase saw him immerse himself in Politics, Archaeology, Philosophy, and the enigmatic realm of Quantum Mechanics. His academic odyssey traversed the venerable corridors of knowledge hubs such as the Museum of London, University College London, Birkbeck College, The City Literature Institute, and Chichester University.

In the symphony of his life, Robert is a custodian of three progeny and a pair of cherished grandchildren. His sanctuary lies ensconced in the embrace of West Wales, where he inhabits an isolated cottage, its windows framing a vista of the boundless sea – a retreat from the scrutinous gaze of the Her Majesty’s Revenue and Customs, an amiable clandestinity in the lap of nature’s embrace.

Exploring Prehistoric Britain: A Journey Through Time

My blog delves into the fascinating mysteries of prehistoric Britain, challenging conventional narratives and offering fresh perspectives based on cutting-edge research, particularly using LiDAR technology. I invite you to explore some key areas of my research. For example, the Wansdyke, often cited as a defensive structure, is re-examined in light of new evidence. I’ve presented my findings in my blog post Wansdyke: A British Frontier Wall – ‘Debunked’, and a Wansdyke LiDAR Flyover video further visualizes my conclusions.

My work also often challenges established archaeological dogma. I argue that many sites, such as Hambledon Hill, commonly identified as Iron Age hillforts are not what they seem. My posts Lidar Investigation Hambledon Hill – NOT an ‘Iron Age Fort’ and Unmasking the “Iron Age Hillfort” Myth explore these ideas in detail and offer an alternative view. Similarly, sites like Cissbury Ring and White Sheet Camp, also receive a re-evaluation based on LiDAR analysis in my posts Lidar Investigation Cissbury Ring through time and Lidar Investigation White Sheet Camp, revealing fascinating insights into their true purpose. I have also examined South Cadbury Castle, often linked to the mythical Camelot56.

My research also extends to the topic of ancient water management, including the role of canals and other linear earthworks. I have discussed the true origins of Car Dyke in multiple posts including Car Dyke – ABC News PodCast and Lidar Investigation Car Dyke – North Section, suggesting a Mesolithic origin2357. I also explore the misidentification of Roman aqueducts, as seen in my posts on the Great Chesters (Roman) Aqueduct. My research has also been greatly informed by my post-glacial flooding hypothesis which has helped to inform the landscape transformations over time. I have discussed this hypothesis in several posts including AI now supports my Post-Glacial Flooding Hypothesis and Exploring Britain’s Flooded Past: A Personal Journey

Finally, my blog also investigates prehistoric burial practices, as seen in Prehistoric Burial Practices of Britain and explores the mystery of Pillow Mounds, often mistaken for medieval rabbit warrens, but with a potential link to Bronze Age cremation in my posts: Pillow Mounds: A Bronze Age Legacy of Cremation? and The Mystery of Pillow Mounds: Are They Really Medieval Rabbit Warrens?. My research also includes the astronomical insights of ancient sites, for example, in Rediscovering the Winter Solstice: The Original Winter Festival. I also review new information about the construction of Stonehenge in The Stonehenge Enigma.

Other Blogs

2024 Prehistoric Britain Blog Review

8000 year-old Cro-Magnon skull

Unmasking the “Iron Age Hillfort” Myth