[6] The insides of the two facing, rectangular uprights have been smoothed off and there is a port-hole at the top of the triangular rear stone, similar to some other dolmens, such as at Trethevy Quoit, in Cornwall.

They would have been able to walk between Continental Europe and Great Britain on dry land, prior to the post glacial rise in sea level, up until between 6,000 and 7,000 BP.

[9] These neolithic colonists integrated with the indigenous people, gradually changing their lifestyles from a nomadic life of hunting and gathering, to become settled farmers.

They built the long barrow at St Lythans around 6,000 BP, about 1,500 years before either Stonehenge or The Egyptian Great Pyramid of Giza was completed.

[10] There are over 150 other cromlechs all over Wales, such as Pentre Ifan in Pembrokeshire (Sir Benfro) and Bryn Celli Ddu, on Anglesey (Ynys Môn), of the same period.

Together with the approximate areas now known as Brecknockshire, Monmouthshire and the rest of Glamorgan, St Lythans was settled by a Celtic British tribe called the Silures.

Commenting on St Lythans in his 'A Topographical Dictionary of The Dominion of Wales', London, 1811, Nicholas Carlisle, says "The Resident Population of this Parish, in 1801, was 72.

"[14] By 1831 the population had grown by over 50% ("Lythan's, St. (St. Lythian), a parish in the hundred of Dinas-Powis, county of Glamorgan, South Wales, 6 miles (W. S. W.) from Cardiff, containing 103 inhabitants.")

[15] St Lythans Burial Chamber is also known as Gwâl y Filiast (English: The Greyhound Bitch's Kennel) — the site had been used as an animal shelter in the early 19th century[7] – and Maes y Felin (The Mill Field), apparently from the legend that, each Midsummer's Eve, the capstone spins around three times and all the stones go to the nearby river to bathe.

[16] The name could be a variant of the Arthurian legend of Culhwch and Olwen, which appears in two fourteenth-century Welsh texts, but the site itself is very much older dating from the Neolithic period, some 5,000 to 6,000 years ago.

[17] Few human remains survive from this period, the early Neolithic (c 6400 BP–5300 BP), although they are comparatively well preserved in the Black Mountains, Gower and the Vale of Glamorgan, where up to 50 individuals, of all ages, have been interred — men, women and children — in each cromlech.

[2] A report noted in 1976 that "Human remains and coarse pottery were found in 1875 in the debris thrown out from the interior, which partly fills the hollow of the original forecourt in the E (sic) end of the mound.

[18] Remains from seven neolithic humans have been excavated from a cave at Goldsland Wood, Wenvoe, near the cromlech at St Lythans, together with pottery and flint blades dating from between 5,000 to 5,600 BP.