Stonehenge

Built in stages over fifteen centuries

The Stonehenge most people picture — the famous trilithons of grey sarsen stone — went up around 2 500 BC. The site had already been in ritual use for more than five hundred years.

A circular earthen ditch and bank with a single Heel Stone outside the entrance dates from about 3 100 BC. The smaller "bluestones" arrived next, hauled or floated 250 kilometres from the Preseli Hills of south-west Wales. Only in the third phase did the massive sarsens, each weighing twenty-five tonnes, arrive from the Marlborough Downs about thirty kilometres to the north.

How a tonne of stone was raised without machinery

The sarsens were dragged on wooden sledges over greased timber rails, hauled by teams of several hundred people for the larger stones.

To lift them upright, the builders dug a pit with a sloped back wall, levered the stone into the pit so it stood vertical, then packed the base with chalk rubble. The lintels — the horizontal stones spanning the trilithons — were raised on platforms of oak timber crib-work, layer by layer, until they reached the top of the uprights and could be tipped sideways into mortise-and-tenon joints carved into the upright stones.

These joinery techniques are borrowed directly from contemporary timber building. The work was done by people accustomed to woodworking, not by any specialised stone-engineering caste.

Who the builders were

Recent DNA analysis of skeletons buried at Stonehenge shows the people who built it were a mixture of two populations: descendants of the original Mesolithic British hunter-gatherers, and later migrants who arrived from Anatolia via continental Europe carrying the new farming economies. They were short by modern standards, lactose-intolerant, mostly dark-haired and dark-eyed.

They lived in scattered round timber houses. The construction workers' village — Durrington Walls, three kilometres away — had communal feasting halls where bones of butchered pigs, cattle and sheep have been found in quantities suggesting seasonal gatherings.

Aligned with the sun

The main axis of the monument points at the midwinter sunset and the midsummer sunrise. A person standing at the centre on the longest day of the year watches the sun rise directly over the Heel Stone outside the circle. The same alignment captures the midwinter solstice in the opposite direction.

The midwinter date was the more important of the two, because that is when feasting bones at Durrington Walls peak. Stonehenge was a monument of the dead and of the deepest moment of the agricultural year — not, despite a stubborn modern association, a place where Druids worshipped.

The Druids appear in the historical record about two thousand four hundred years later.