Hilda of Whitby was the grand-niece of Edwin of Northumbria. In 627 Edwin and his household were baptized Christian. When Edwin was killed in the Battle of Hatfield Chase, the widowed Queen Æthelburh, her children, and Hilda returned to Kent, now ruled by Æthelburh's brother, Eadbald of Kent. Æthelburh established Lyminge Abbey, one of the first religious houses to be founded in England. It was a double monastery, built on Roman ruins. Æthelburh was the first abbess. It is assumed that Hilda remained with the Queen-Abbess. Nothing further is known of Hild until around 647 when having decided not to join her older sister Hereswith at Chelles Abbey in Gaul, Hild returned north. (Chelles had been founded by Bathild, the Anglo-Saxon queen consort of Clovis II.) Hild settled on a small parcel of land near the mouth of the river Ware, where under the direction of Aidan of Lindisfarne, she took up religious life. In 649, he appointed her abbess of the double monastery of Hartlepool Abbey, previously founded by the Irish recluse Hieu. In 655, in thanksgiving for his victory over Penda of Mercia at the Battle of the Winwæd, King Oswiu brought his year old daughter Ælfflæd to his kinswoman Hilda to be brought up at the abbey. (Hild was the grand-niece of Edwin of Northumbria; Oswiu was the son of Edwin's sister Acha.) Two years later, Oswiu established a double monastery at Streoneshalh, (later known as Whitby), and appointed Hild abbess. Ælfflæd then grew up there. The abbey became the leading royal nunnery of the kingdom of Deira, a centre of learning, and burial-place of the royal family.