Trahans ARE of Welsh ancestry after all: Surname = Trahaearn
by Fabian Pierre Trahan
Re: King Trahaearn ap Caradog Welsh King who died at the Battle of Carno circa 1080 C.E.
Q: How did descendants of Roman Emperor Trajan end up in Wales??
A:"Welsh kings would later use the authority of Magnus Maximus as the basis of their inherited political legitimacy. While imperial Roman entries in Welsh royal genealogies lack any historical foundation, they serve to illustrate the belief that legitimate royal authority began with Magnus Maximus. As told in The Dream of Emperor Maximus, Maximus married a Briton, and their supposed children are given in genealogies as the ancestors of kings. Tracing ancestries back further, Roman emperors are listed as the sons of earlier Roman emperors, thus incorporating many famous Romans (e.g., Constantine the Great) into the royal genealogies. The kings of medieval Gwynedd trace their origins to the northern British kingdom of Manaw Gododdin (located in modern Scotland), and they also claim a connection to Roman authority in their genealogies ("Eternus son of Paternus son of Tacitus"). This claim may be either an independent one, or was perhaps an invention intended to rival the legitimacy of kings claiming descent from the historical Maximus. Gwyn A. Williams argues that even at the time of the erection of Offa's Dyke (that divided Wales from medieval England) the people to its west saw themselves as "Roman", citing the number of Latin inscriptions still being made into the 8th century."
Williams, Gwyn A., The Welsh in their History, published 1982 by Croom Helm, ISBN 0-7099-3651-6