Infamous Vortigern. What more can one say. Manuscripts published around the time that Tudor Trevor was born ca. 900 AD, continued the accounts of Vortigern. A Welsh manuscript translated by William Cooper contains more stories about grandfather Vortigern. This manuscript, written in Welsh, first sets the stage:
"And when Constantine was dead, there arose a great dispute amongst the nobles of the realm concerning the election of a new king. Some wished to have Ambrosius for their king, but others were swayed towards Uther, whilst yet others wished to make one of their own friends be king."
Constantine III was proclaimed emperor in Britain 407AD and led a revolt against central Rome authority. He ruled from Arles, and Britain revolts from his claims around 409AD. He falls 411AD, thus completely ending any Roman rule in Britain. It was after this year, that the "nobles of the realm" met to discuss what was to be done.
The manuscript continues:
"But at the last, when no agreement could be reached between them, there came Vortigern before them. And he was one of the elders of the land of Britain whose wisdom was deemed the highest."
As far as I know, this is the best words that any of the writers had to say about Vortigern. A wise elder of the land! From this point all else is down hill. Vortigern is given credit for setting up one of the sons of Constantine as the new king. He then gets the Picts to kill this new king because he (Vortigern) really wanted to be king himself. He then leaves the Picts to their own blame who get hung by those Britons who blame Vortigern. This action then excited the Picts to take vengeance upon the Britons, who then need the Saxons to help fight the Picts. When the Saxons succeed, the Britons then rebelled against the Saxons and Vortigern, led by the very sons of Vortigern. This throws Vortigern out of power, only to return after his eldest son is killed by poison from the hand of Vortigern's Saxon wife. The Saxons and Vortigern return to power, only to have the Saxons drive Vortigern to the western most part of the island...where the world ends!
Wow, sounds like one of those soap operas on afternoon T.V. At any rate, when Tudor born at a small hamlet called Trevor (Trefor) around 900 AD came into this world, you might understand how the family would not want to advertise that they were a direct descendant from this Benedict Arnold of the Welsh world!
The Welsh manuscript is called "Brut y Bryttaniait", "The Chronicle of the Early Britons". It is found at Jesus College MS LXI. An annotated translation is given by William R. Cooper MA, Phd, ThD. The story of Constantine III is given in the text by Peter Salway, "The Oxford Illustrated History of Roman Britain", starting p. 303.