What is Oswiu of Northumbria?
'''Oswiu''' ({{circa|611}}–15 February 670), also known as '''Oswy''' or '''{{lang-ang|Ōswīg}}''', became the King of [[Bernicia]] at the death of his brother [[Oswald of Northumbria|Oswald]]. Later he became the King of [[Northumbria]]. When Oswiu defeated and killed [[Penda of Mercia]] at the [[Battle of the Winwaed]], he became the seventh [[:en:wikt:Bretwalda|bretwalda]] over the southern [[Anglo-Saxons|English]] kings. He took the throne of [[Mercia]] and appointed his son-in-law [[Peada of Mercia|Peada]] (Penda's son) as a client king. Oswiu was one of those rare kings of Northumbria who died of natural causes and not in battle. == Early career == Oswiu was born {{circa|611}}<ref name=Ashley281>Mike Ashley, ''The Mammoth Book of British Kings and Queens'' (New York: Carroll & Graf, 1999), p. 281</ref> He was a son of King [[Athelfrith of Bernicia]] and his second wife Acha of [[Deira]]. He was a younger brother of King Oswald of Northumbria.<ref name=Abraham26>Rudolf Abraham, ''St Oswald's Way and St Cuthbert's Way'' (Milnthorpe, Cumbria: Cicerone, 2013), p. 26</ref> When he was about 6 years old his father was killed in battle by [[Edwin of Deira|Edwin]] who became King of [[Northumbria]].<ref name=Marsden108>John Marsden, ''Northanhymbre Saga; the History of the Anglo-Saxon Kings of Northumbria'' (London: Kyle Cathie Limited, 1992), p. 108</ref> Along with his brothers [[Eanfrith of Bernicia|Eanfrith]] and Oswald and their sister Aebbe, he found safety with the [[Scottish people|Scots]] in [[Dál Riata]].<ref name=Marsden108/> The monks of Iona [[baptized]] the children and raised them in the [[Celtic Christianity|Celtic Christian]] faith.<ref>Mike Ashley, ''The Mammoth Book of British Kings and Queens'' (New York: Carroll & Graf, 1999), p. 279</ref> About 634 Oswiu married Rhiainmelt, daughter of Rhoeth of [[Rheged]], a marriage [[:wikt:alliance|alliance]] arranged by his brother King Oswald.<ref name=Ashley281/> He had a son by this marriage, [[Alfrith of Deira]]. Rhiainmelt seems to have died as a ye