Æthelfrith of Northumbria

thumb|200px|right|The main Anglo-Saxon Kingdoms in the 7th century. Æthelfrith (died ) was King of Bernicia from c. 593 until his death around 616 AD at the Battle of the River Idle. He became the first Bernician king to also rule the neighbouring land of Deira, giving him an important place in the development and the unification of the later kingdom of Northumbria. Reigning from the late 6th century until his death, he was known for his military campaigns against the Britons and his victory over the Gaels of Dál Riata. His most famous victory came at the Battle of Chester, where he decisively defeated a coalition of British forces, significantly weakening the influence of the native Britons in northern England. Æthelfrith's rule marked a turning point in the consolidation of Northumbria as a dominant force in early medieval Britain. He was killed in battle against a coalition led by Rædwald of East Anglia, who placed Edwin, the exiled heir of Deira, on the throne. His line was eventually restored to power in the 630s.

== Background == Æthelfrith, son of Æthelric and grandson of Ida, apparently succeeded Hussa as king of the Bernicians around the year 592 or 593; Æthelfrith's accession may have involved dynastic rivalry and the exile of Hussa's relatives. The genealogies attached to some manuscripts of the Historia Brittonum say that Æthelfrith ruled Bernicia for twelve years and ruled Deira for another twelve years, which can be taken to mean that he ruled in Bernicia alone from about 592 to 604, at which point he also came to the throne of Deira. His predecessors are obscure; Æthelfrith is the earliest Bernician ruler about whom any significant details are known. The 20th-century historian Frank Stenton wrote that "the continuous history of Northumbria, and indeed of England, begins with the reign of Æthelfrith", and that "he was the real founder of the historic Northumbrian kingdom, and he was remembered as the first great leader who had arisen among the northern Angles."