 In 662, Swithelm of Essex was persuaded to adopt Christianity and was baptised at Rendlesham, with Æthelwold present as his sponsor.East Anglia became more closely allied to Northumbria, Kent and lands in the Fens by means of royal marriages such as that between the Northumbrian Hereswitha and the East Anglian Æthilric.The history of East Anglia and its kings is known from "The Ecclesiastical History of the English People", compiled by the Northumbrian monk Bede in 731, and a genealogical list from the "Anglian collection", dating from the 790s, in which the ancestry of Ælfwald of East Anglia was traced back through fourteen generations to Wōden.