Penda and Cadwalla met after the slaughter. As the former was wounded, he determined to return to Mercia, after making a bargain for a share of the plunder. Cadwalla dispersed his army in large parties, moving northwards to kill, harry, and destroy. The Welshmen committed every conceivable atrocity: neither age nor sex was spared, and the savages revelled in their cruelty. Bilbrough and Ulfskelf were sacked. Hemingborough escaped, but of Stillingfleet not a vestige was left, and the ancient buildings of Aldby were levelled with the ground. Few houses escaped their fury. Finally, they occupied York itself, where there were new scenes of devastation and horror.
Osric collected the remnant of the Deirans at Driffield, who proclaimed him their King. He declared that he adhered to the religion of his ancestors, and if the wretched old Coifi had not died soon after he polluted the sanctuary of Woden, he would probably have been taken to Godmundham and put to death. After months of preparation, Osric advanced to York, where the King of Gwynedd still remained. The King of Deira attacked the Decumanian Gate; but Cadwalla sallied out with his whole army and put the English to flight. Osric was himself among the slain. Cadwalla then marched northwards to subdue the Bernicians. On the death of Edwin, the sons of Ethelfrith had returned from their exile among the Picts, and the eldest, Eanfrid, had been accepted as King of Bernicia. On the approach of the ferocious Welsh King, he sued for peace, and it was arranged that there should be an interview. Eanfrid came to the enemy's camp with six attendants, and was foully murdered by Cadwalla. Eanfrid had also adhered to the religion of his ancestors. Consequently both these gallant young princes, Osric and Eanfrid, are vilified and slandered by the monks.
Oswald, the son of the peerless Alca, then succeeded, and was joyfully received, both by the Bernicians and Deirans, as their King. He saw that there could be no terms with the faithless Welshman—he must be stamped out. Cadwalla was in the neighbourhood of Hexham, near the Great Wall. When Oswald reached a spot called Heavenfield, he put up a cross, helping to fix it in the ground himself. Then, raising his voice, he cried to his army, "Let us all kneel and jointly beseech the true and living God Almighty in His mercy to defend us from the haughty and fierce enemy. He knows that we have undertaken a just war for the safety of our nation." Advancing towards the enemy at dawn, he gained a great victory, and Cadwalla was killed at a place called Denisburn, perhaps Dilston.
Oswald came to York, and visited the melancholy ruins of Aldby, where his happy childhood had been passed with his mother, and where he had been torn from the arms of Bergliot by the savage Ethelfrith. He consulted with Sivel, and encouraged him to persevere with the work of building the church of St. Peter at York until it was completed. Oswald applied to the monks of Iona for a bishop, and in 635 they sent him a devout man named Aidan, to whom he assigned the island of Lindisfarne as his episcopal see. "A man of singular meekness, piety, and moderation, and zealous in the cause of God." Oswald was acknowledged as Bretwalda of all Britain in succession to his uncle, Edwin the Great, and "when raised to that height of dominion he always continued humble, affable, and generous to the poor and strangers." The ruthless savage Penda had to add one more crime to the long list before his cup was full. He invaded Northumbria, and killed the good and saintly Oswald at the battle of Maserfield, probably at Winwick in Lancashire, in the year 642. Oswald's niece Osfrith, Queen of the Mercians, translated her uncle's bones to the Abbey of Bardney in Lincolnshire in 697, and in 909 they were removed into Mercia. The monks traded much with them, as a means of working miraculous cures.
Oswald was succeeded in Bernicia by his half–brother Oswy, who had received a mother's care from Queen Alca, though not her son. He usurped the rights of Oswald's son Ethelwald, the grandson of Alca. In Deira Oswin became king in succession to his father Osric. This excellent prince had been brought up by Bergliot with the sons of Lilla, to whom he was warmly attached. Trondhere, the eldest, became his adviser and constant companion. The younger son, Trumhere, entered the priesthood. During the first year of Oswin's reign the Princess Bergliot died, and was buried by her sons, by Lilla's side, in the old Roman fort at Hemingborough. Oswin was a man of wonderful piety and devotion, and governed Deira very prosperously, with the aid of Sivel, Trondhere, and Bishop Aidan, during seven happy and prosperous years. He was tall and graceful, affable and always courteous, and most generous, so that he was beloved by all ranks of the people. He was warmly attached to Aidan, who was astonished at his humility, a virtue rare in kings.
A story was recorded by Sivel, and repeated by Bede, which exemplifies this virtue. The King had given Aidan an extraordinarily fine horse, either to use in crossing rivers or in any extraordinary emergency, for ordinarily the Bishop travelled on foot. Soon afterwards, meeting a beggar, Aidan dismounted and presented the horse, with all its royal furniture, to the miserable creature. This was told to the King when he and the Bishop were going in to dinner. Oswin said, "Why did you give the beggar that royal horse which was necessary for your use? Are there not many other horses of less value which would have been good enough to give to the poor?" Aidan answered, "What is it you say, O King? Is that foal of a mare more dear to you than the Son of God?" Upon this they went in to dinner, and the Bishop sat in his place, but the King, who had just returned from hunting, stood warming himself, with his attendants, at the fire. Suddenly, calling to mind what the Bishop had said to him, Oswin ungirt his sword, gave it to a servant, and hastily knelt before the Bishop asking forgiveness. Aidan was much moved, and, starting up, raised the King, saying he was entirely reconciled, if he would sit down at meat and lay aside all sorrow. The King then began to be merry. The Bishop, on the other hand, became so melancholy as to shed tears. His priest asked him in Gaelic why he wept. In the same language Aidan answered, "I weep because I know the King will not live long. For I never before saw so humble a king, whence I conclude that he will soon be snatched out of this life, for this nation is not worthy of such a ruler."
It was too true. In 650 the ambitious Oswy collected a great army to invade Deira. Oswin assembled a smaller force, and advanced, with Trondhere, to Catterick. But finding that the King of Bernicia had a much larger number of troops, he dismissed his men to their homes to avoid useless bloodshed, resolving to go into concealment until better times. A certain Earl named Hunwald promised him a safe place of retirement at Gilling. But Hunwald was a traitor. The place was betrayed to Oswy. On the 20th of August 650 a commander named Ethilwin and several followers forced their way into the house. Like his father Lilla before him, Trondhere threw himself before his master to protect him from the blows of the assassins. But in vain. He was slain and thrown aside, and then the good King Oswin was despatched. One may hope that this was not done by order of Oswy, and that, as in the case of Henry II. and Becket long afterwards, he was only guilty of a hasty word misinterpreted by an unscrupulous servant. For some time the crime was concealed.
It was not known to Sivel, who could hardly have taken a lenient view of the King's conduct, when bitterly resenting the murders of the son of Lilla and of the nephew of Hereric. But he was even then on his death–bed. During the reign of Oswin the last of Edwin's paladins had been chief of the Billingas, but he had resigned the duties and given up all his rights to Saebald's grandson Osbert, whose two brothers, named Adda and Utta, had become priests. For Sivel was now advanced in years. He lived at York, occupied with his chronicle, his coinage, and the completion of King Edwin's church of St. Peter, or York Minster. His cousin Utta had been one of his clerks, and had since taken orders, but continued to attend on Sivel in his old age. At last his long and useful course was finished, having reached his seventy–first year, and survived all his friends. More than two hundred years afterwards there was a moneyer at York of the same name, who struck coins for King Edwig, and who may not improbably have been a descendant of Sivel's cousin Saebald. Osbert, Adda, and Utta conveyed the body of the last surviving paladin of Edwin the Great from York to Bilbrough. They buried Sivel in the tumulus of his father Vidfinn, by the side of his beloved Forthere. The tumulus was then raised to nearly twice its present height.
Adda became Abbot of Gateshead, and was afterwards employed in the conversion of the Mercians. Utta was "a man of great gravity and sincerity, and on that account honoured by all men, even the princes of the world." When King Oswy resolved to send an embassy to Ercombert, King of Kent, who had succeeded to his father Eadbald, in 641, to ask for the hand of the daughter of Edwin the Great, he had consulted Sivel with regard to the selection of an ambassador, who recommended his cousin Utta. But the mission did not start until after the funeral of Sivel. King Oswin, Bishop Aidan, and Sivel died within a week of each other; and soon afterwards the mission left York.
Bishop Aidan, before his death on 31st August 650, made an excellent suggestion to Utta. He thought it likely that a storm would be encountered either going or returning, and he gave Utta a keg of oil, saying that if he threw it overboard the rough sea would become smooth. The experiment was remarkably successful, as Bede was told by a priest named Cynemund, who had it from Utta himself.