These forts are likely to have been centres of power of the Votadini, who were the subject of the poem Y Gododdin which is thought to have been written about 600 AD in their hillfort on Edinburgh castle crag.
The most well known poem contained within its pages is Y Gododdin, an early Welsh-language poem commemorating the warriors from Gododdin (Lothian in modern Scotland) who fell at the Battle of Catraeth (probably Catterick in North Yorkshire) around the year 600.
The Votadini or Gododdin, are thought to have been the first to defend this site, the Brythonic name Dyn Barr, (the fort of the point) is still in use.
There was a Welsh hero Eidiol mentioned in The Gododdin who may have inspired the use of the name in Geoffrey's work.
His works include The Celtic Heroic Age (first published in 1994, 4th edition in 2003), in collaboration with John Carey; The Gododdin of Aneirin (1997), an edition, translation and discussion of the early Welsh poem Y Gododdin; and numerous articles published in books and journals.