Barnenez

The Cairn of Barnenez, also known as the Barnenez Tumulus or Mound, is a Neolithic monument near Plouezoc'h, on the Kernéléhen peninsula in northern Finistère, Brittany, France. It dates to the early Neolithic, around 4000 BC. With the Tumulus of Bougon and the Locmariaquer megaliths, it is one of the earliest megalithic monuments in Europe and one of the oldest man-made structures in the world. It is also remarkable for its megalithic art.

Today the cairn is 72 m long, up to 25 m wide and over 8 m high, built of 13,000 to 14,000 tons of stone. It has steep facades and a stepped profile, and it contains 11 chambers, each entered by its own passage. The mound consists of relatively small blocks, with only the chambers being truly megalithic. It overlooks the Bay of Morlaix, probably a fertile coastal plain at the time it was built.

Radiocarbon dates indicate that the first phase was erected between 4850 and 4250 BC and the second phase between 4450 and 4000 BC. In the first phase a slightly trapezoidal mound of 32 m by 9 to 13 m was built, with 5 chambers and a double kerb, favouring dolerite. In the second, an extension with six further chambers was added in the west, and the first cairn was enveloped in a wider and taller structure, with more granite used. Estimates suggest the first cairn alone would have taken 200 workers three months to erect.

The 11 chambers are of the type the French call dolmen à couloir, or passage grave, built of large slabs of slate and granite. Each is reached from the southeast by a long narrow passage (7–12 m long), and the passages run parallel. In nine cases the passages lead to corbelled chambers, and in one the corbel vault sits on the ground, forming a true tholos. Engraved symbols in several chambers and passages show bows, axes, wave symbols or snakes and a repeated U-shaped sign, and one recurring symbol is sometimes read as the so-called 'Dolmen Goddess'.

The cairn was first mapped in 1807 and recognised scientifically at a congress in Morlaix in 1850. Privately owned until the 1950s, it was used as a quarry for paving stones, which threatened to destroy it until several chambers were discovered in the 1950s and the local community took control. It was restored between 1954 and 1968. Pottery shows reuse in the Bronze Age, in the 3rd millennium BC. Similar monuments are known at 22 other locations in France and on Jersey.

Dates

Radiocarbon dates indicate that the first phase of the monument was erected between 4850 and 4250 BC, and the second phase between 4450 and 4000 BC.

Secondary use

Pottery found in and around the monument indicates that it underwent a period of reuse in the Bronze Age, in the 3rd millennium BC.

Recognition as an ancient monument

The cairn was first mapped in 1807, in the context of the Napoleonic cadaster. Its first scientific recognition took place in the context of an academic congress in Morlaix in 1850, when it was classified as a tumulus.

Quarry damage

Privately owned until the 1950s, the cairn was used as a quarry for paving stones. This activity, which threatened to destroy the monument, was only halted after the discovery of several of its chambers in the 1950s. The local community then took control of the site.

Restoration and excavation

The cairn was restored between 1954 and 1968. At the same time, vegetation was removed from the mound and systematic excavation took place in and around the monument.