Theodric ruled from 572 to 579. He was the fifth known ruler of the Anglo-Saxon

Anglo-Saxons

Anglo-Saxon is a term used by historians to designate the Germanic tribes who invaded and settled the south and east of Great Britain beginning in the early 5th century AD, and the period from their creation of the English nation to the Norman conquest. The Anglo-Saxon Era denotes the period of...

 kingdom of Bernicia

Bernicia

Bernicia was an Anglo-Saxon kingdom established by Anglian settlers of the 6th century in what is now southeastern Scotland and North East England....

.

Theodric was the son of Ida of Bernicia

Ida of Bernicia

Ida is the first known king of the Anglian kingdom of Bernicia, which he ruled from around 547 until his death in 559. Little is known of his life or reign, but he was regarded as the founder of a line from which later Anglo-Saxon kings in this part of northern England and southern Scotland...

, founder of the kingdom of Bernicia. Little is known of Theodric's life and reign although Urien

Urien

Urien , often referred to as Urien Rheged, was a late 6th century king of Rheged, an early British kingdom of the Hen Ogledd . His power and his victories, including the battles of Gwen Ystrad and Alt Clut Ford, are celebrated in the praise poems to him by Taliesin, preserved in the Book of Taliesin...

, the king of Rheged

Rheged

Rheged is described in poetic sources as one of the kingdoms of the Hen Ogledd , the Brythonic-speaking region of what is now northern England and southern Scotland, during the Early Middle Ages...

, was said to have subjected Theodric and his sons to a three day siege on the island of Lindisfarne

Lindisfarne

Lindisfarne is a tidal island off the north-east coast of England. It is also known as Holy Island and constitutes a civil parish in Northumberland...

. According to medieval Welsh poetry (such as the poem Gweith Argoed Llwyfain (The Battle of Argoed Llwyfain or Battle of Leeming Lane) from the Book of Taliesin

Book of Taliesin

The Book of Taliesin is one of the most famous of Middle Welsh manuscripts, dating from the first half of the 14th century though many of the fifty-six poems it preserves are taken to originate in the 10th century. The manuscript, known as Peniarth MS 2 and kept at the National Library of Wales,...

), Theodric was killed in battle by Urien's son, Owain mab Urien

Owain mab Urien

Owain mab Urien was the son of Urien, king of Rheged c. 590, and fought with his father against the Angles of Bernicia. The historical figure of Owain became incorporated into the Arthurian cycle of legends where he is also known as Ywain, Yvain, Ewain or Uwain...

, after Theodric demanded hostages and Owain refused to give in.

The dates for Theodric's rule are conjecture; the earliest authorities differ widely on the order and the regnal years of the kings between the death of Ida and the beginning of Æthelfrith's

Æthelfrith of Northumbria

Æthelfrith was King of Bernicia from c. 593 until c. 616; he was also, beginning c. 604, the first Bernician king to also rule Deira, to the south of Bernicia. Since Deira and Bernicia were the two basic components of what would later be defined as Northumbria, Æthelfrith can be considered, in...

rule in 592/593.