Until the early 1930s, near the mound of Midhowe, in south-western Rousay, was a large, oblong, grassy knoll.

Measuring 100 feet long and about 30ft wide, the mound was crested by a “modern” drystane dyke

In 1932, the landowner, and whisky magnate, Walter Grant, of Trumland House, began a series of excavations that gradually revealed the remains of a stalled burial chamber.

Thought to date from around 3500BC, they compared the structure to a “long, narrow byre”.

Working down through the stones, from the collapsed roof, the excavators uncovered a 23-metre long chamber, divided by upright flagstones into a series of 12 stalls.

Each of these stalls contained a stone “bench” on which bodies had been laid.

The remains of 25 individuals – 17 adults, six youths and two children under four  - were found on the floor of the cairn.

The corpses had been placed with their backs to the eastern wall, thus facing the central passage.

Those at the southern end of the cells lay on their left side and those at the northern end on their right.

Most of the skeletal remains had been deposited on the top of the low shelves, between the divisional slabs.

Only four deposits were found under the shelves and three on the floor, without any structural arrangements.

Because no human remains were found in the first four cells, it was suggested that bodies were placed in the cells near the entrance and left till the flesh had rotted away.

Some time later, the bones were collected and deposited further inside the structure.

Throughout the rubble that filled the cairn, the excavators found the remains of cattle, sheep and red-deer (antlers), as well as fishbones and limpet shells.

Like other Orkney cairns, the finds hint at either ritual feasting around the site, or were perhaps grave goods, “buried” along with the dead.

Other artefacts in the rubble included five hammer-stones, a stone pestle and three  “rude stone implements”.

After the tomb had fallen out of use, two corpses were buried into the collapsed rubble.

The first, a man, was buried in the south-west corner of cell four, while the other lay in the north-west corner of the cell.

The second corpse, which may have been a woman, had been interred in a rough cist-like structure made from flat stones. Like the man, the second body had been buried in a foetal position, on its right side, with its head to the south.