sentences:  Pehthelm's historical significance is largely confined to his status as the first bishop in the newly created diocese.Historical context
  
  The Kingdom of Northumbria was ascendant from the seventh through the ninth centuries, and it was the premier regional power in Great Britain between the Humber and the Firths of Clyde and Forth.At the Synod of Whitby in 664, King Oswiu repudiated the Celtic Christianity (so called, and also called Columban after its most notable proponent) that had previously been dominant in the northern Northumbrian territory of Bernicia, and aligned Northumbria with the continental church organisation favoured by Northumbria's southern neighbors.