When the terrible Penda had advanced into Northumbria, against Oswy, destroying homesteads and harvests with fire, and butchering all who fell into his hands, then the Northumbrian king sent presents to him, and asked for peace. The fierce Mercian refused the presents offered: nothing would satisfy him but the absolute subjection of the Northern Kingdom. Then, in despair, Oswy vowed to God that, as the old Pagan had rejected his gifts, he would dedicate his little one-year-old daughter to Him, together with twelve farms, if He would bless his arms in battle. The odds were against Oswy. The host opposed to him was thrice as numerous as his own. Ethelhere, King of the East Angles, had come to the aid of Penda; and Odilwald, son of S. Oswald, who had been given an underlordship of part of Deira, and who thought he ought to have succeeded his father in kingship, went over to Penda. The battle was fought on the Winwaed, near Leeds; the Mercians and their allies in their confidence had incautiously put the river at their back. Heavy rains filled it to overflow; it became a deep and boiling torrent, cutting off retreat. The Mercians were defeated. A panic fell on them, and as they fled they were swept away by the swollen river. Of the thirty eorldormen who marched with Penda, hardly one survived. The King of the East Angles and the savage old Mercian were among those who were slain. Odilwald did not enter the battle. He was well aware that when Bernicia had been eaten, Penda’s next mouthful would be Deira. He bore a bitter grudge against Oswy, but for all that did not care to put the knife into the hand of the Mercian king wherewith to have his own throat cut. A battle song was composed on the occasion, of which a snatch has been preserved:— “In the river Winwaed is avenged the slaughter of Anna, The slaughter of Sigbert and Ecgric as well, The slaughter of Oswald and Edwin who fell.” The battle was fought in 655, consequently S. Elfleda was born in 654. Oswy faithfully kept his vow. He set apart twelve estates to be thenceforth monastic property—six in the north and six in the south of his double kingdom. He then surrendered the little Elfleda to be brought up to the service of God. Her mother was Eanfleda, daughter of Edwin, the first Christian King of Northumbria. It was, in fact, her birth, on Easter Day, 626, which was the occasion of the subsequent conversion of her father, and of his subjects; and Eanfleda was the firstfruits of her nation to receive baptism on the Whit Sunday following. Oswy, the father of Elfleda, was a dissolute and murderous ruffian, who in cold blood had murdered the gallant Oswin, King of Deira, the kinsman of his own wife. Oswy gave his daughter to S. Hilda, at Hartlepool.