First Dynasty of Gwynedd

The First Dynasty of Gwynedd was the founding dynasty of the Kingdom of Gwynedd, and ruled over the kingdom for almost four hundred years. Its main branch may also be referred to as the Maelgyning, named after Maelgwn Gwynedd, an important king of the dynasty. This branch was based in Aberffraw. Its other main branch was descended from Cynlas, and was based in Rhos. The two branches at times competed for the title of king.

The members of the family claimed descent from Cunedda Wledig, who in legend arrived in Wales sometimes in the fifth century from the Brittonic-speaking areas north of Hadrian's Wall and led a campaign of ethnic cleansing against the Irish who had settled in Wales in the previous decades, founding the kingdom of Gwynedd in the process. The family ruled Gwynedd until the succession to the kingdom by the Aberffraw by Merfyn Frych, a ruler from the Isle of Man whose mother was a descendant of Cunedda. Many noble families in medieval Wales claimed descent from Cunedda in the High Middle Ages even as the First Dynasty's rule over Gwynedd had been eclipsed centuries earlier.