Oswin succeeded Oswald as king and ruled Deira a southern province of Northumbria for seven years. Educated by Aidan he was greatly beloved by his people. It is recorded that he was "of rare humility and virtue" and that "courtesy shone from him".
Not only had Adian mentored the King, they were dear friends. Oswin once tried to give him a horse to make travel easier. Adian gave the horse away to the first begger asking alms.
Bede records an insident that took place shortly before Oswin's death: "They went in to dinner and the bishop sat down in his place whilst Oswin warmed himself by the fire. Suddenly, the king unbuckled his sword belt, knelt at the bishop's feet and begged his forgiveness, and promised never again to question how much of his bounty the bishop gave to God's children. The bishop was deeply moved, raised Oswin to his feet, and begged him to sit down to his food.
As the king and his party grew merrier, so the bishop became sadder until he shed tears. His chaplain asked him what was wrong, and the bishop replied, "I know the king will not live long, for I have never before seen a humble king. I feel he will soon be taken from us, because this nation is not worthy of such a king".
He was murdered the 20th of Agust 651 at Gilling in Yorkshire England on order of his jelous cousin Osway.