From Wikipedia - https://en.wikipedia.org/wiki/Crimthann_mac_Fidaig According to the Sanas Cormaic,[3] Crimthand Mór mac Fidaig built a great fortress in Cornwall known as Dind Traduí or Dinn Tradui (Dun Tredui/e, fortress of the three ramparts).[4] There appears to be little doubt that it existed,[5] and British archaeologists and linguists have attempted to identify it with a number of sites in Cornwall and in Wales as well, for example, Din Draithou,[6] which is phonetically similar. Din Draithou is widely thought to be the modern Dunster, or the nearby Iron Age hillfort Bat's Castle.[7] It may also be associated with Dind map Letháin, a colonial fortress constructed by the related Uí Liatháin, earlier form Létháin,[8] kingdom of Munster, who is known to have been active in Britain for centuries. They may have retreated to South Wales or Cornwall after being expelled from North Wales by Cunedda, as mentioned in the Historia Brittonum.[9] In a 1926 paper, Eoin MacNeill discusses the movements of the Uí Liatháin at considerable length, arguing their leadership in the South Irish conquests and the founding of the later dynasty of Brycheiniog, the Welsh genealogies matching Uí Liatháin dynasts in the Irish genealogies. He argues any possible settlement of the Déisi in Wales would have been subordinate until the ousting of the Uí Liatháin by the sons of Cunedda. The founder of Brycheiniog, Brychan, is in all probability the early Uí Liatháin dynast Macc Brocc, while the name Braccan also occurs early in the pedigrees of the Uí Fidgenti and Uí Dedaid, close kindred of the Uí Liatháin. MacNeill further associates this with the sovereignty in Ireland and conquests in Britain of their cousin germane, the monarch Crimthann mac Fidaig.[10] Crimthand Mór mac Fidaig and the early Uí Liatháin may have belonged to the historical Attacotti (circa 368). Note the correspondence of date FamilySearch.org gives 4 potential parents none of which match up with the above from Wikipedia.