Gododdin

The kingdom of Gododdin was founded in 455 by Ambrosius Aurelianus. After the Saxon betrayal of Gworthigern (not stopping him from using their military help), as well as the latter's own sons turning against him, Ambrosius landed in Devon with his brother Uther and came to the lands of the Gododdin tribes and united them. Eager for glory, understanding of Ambrosius' cause, that is to regain his birthright, and also interested in emulating the Southern Kingdoms popping up, they accepted and formed the Kingdom of Gododdin.

Ambrosius died three years later in combat at the Battle of Guoloph, 458 AD. Pasgen, the only son loyal to Gworthigern and later an ally of the Welsh Irish, killed him. Uther later avenged his brother at the Battle of Mynyw in 488 AD, against Pascent, his Irish ally Gillomanius and their Saxon allies.