The chief of these appe a r to have been Urien, who is said to have fought against the Northumbrian king Theodoric, and Rhydderch Hen who is mentioned also in Adamnan's Life of S.
Rhydderch Hen appears to have secured the supremacy amongst these Welsh princes after the great battle of Ardderyd fought about the year 573, to which frequent reference is made in early Welsh poetry.
The following is a list of kings whose names are mentioned in the chronicles: Rhydderch Hen.
603 Constantine son of Rhydderch (?) Iudruis (?) d.
After the battle of Ardderyd in 573 in which King Rhydderch, leader of the Christian party in Strathclyde, was victorious, Kentigern was recalled.