Meurig ap Tewdrig (Latin: Mauricius) was the son of Tewdrig (St. Tewdrig), and a king of the early Welsh kingdoms of Gwent and Glywysing. He was in power some time before 470 AD.
Meurig took over the Gwent throne upon his father's abdication. According to tradition, Tewdrig became a hermit at Tintern, but later came to the assistance of Meurig, and they repelled the invading Saxons in a battle at Pont y Saeson (Bridge of the Saxons). Tewdrig died after the battle, and Meurig buried him at Mathern, giving the surrounding land (including the area of the later village of Pwllmeurig, named after Meurig), in his memory to the bishops of Llandaff.
Meurig reunited his kingdom with Ergyng (Archenfield) by marrying Onbrawst, the daughter of Gwrgan Fawr (the Great), the ruler of that kingdom. He was later claimed to have been a great patron of the ecclesiastical centre at Llandaff, where he is said to be buried.
He was the father of Athrwys ap Meurig, one of a number of figures that researchers have claimed as the "real King Arthur". Athrwys is believed to have pre-deceased Meurig, who was succeeded by his grandsons, Ithel and Morgan Mwynfawr.
Tewdrig [ˈtɛudrɪg] [ˈtɛudrɪg ap ˈtɛiθvaɬt] (Latin: Theodoricus) (Welsh: Tewdrig ap Teithfallt) was a king of the post-Roman Kingdom of Glywysing. He abdicated in favour of his son Meurig (Maurice) and retired to live a hermitical life, but was recalled to lead his son's army against an intruding Saxon force. He won the battle, but was mortally wounded.
The context of the battle is one of Britons versus invading Saxons, without explicit religious overtones. However, since Tewdrig held to a religious lifestyle and was killed while defending a Christian kingdom against pagans, by the standards of that day Tewdrig is considered to be a martyr and a saint. The Latin form of his name is given as 'Theodoric' and his feast day is April 1. Tewdrig's name appears in a genealogy of Jesus College MS 20, in the line of one of his descendants, but the only substantive information about the person comes from the twelfth century Book of Llandaff.
The Book of Llandaff places Tewdrig's story in the territory of the historical Kingdom of Gwent (the southeastern part of modern Monmouthshire), though it states that he was a king of Glywysing. The ancient histories of the kingdoms of Gwent and Glywysing are intertwined, and he may have ruled both kingdoms.