Tewdr, Kings of Brycheiniog
Tewdr was the second son of King Rhein of Dyfed & Brycheioniog. In the mid-8th century, he inherited the Kingdom of Brycheioniog, while his brother, Tewdos, took on Dyfed. However, Tewdr had a rival in the person of Elwystl ap Awst, probably his cousin, who also claimed to be rightful King of Brycheiniog. The two were persuaded to live peacefully side-by-side and to this end they swore an oath on the altar of St.Dyfrig (probably at Gwenddwr). Tewdr soon broke the peace though and brutally murdered Elwystl. He was forced to give up Llanfihangel Cwm Du to the Church for his misdemeanour but his reign continued.