dedicated to reforming and reorganising the English church. Stigand and his brother, Æthelmær, the Bishop of Elmham, were deposed from their bishoprics. Some of the native abbots were also deposed, both at the council held near Easter and at a further one near Whitsun. The Whitsun council saw the appointment of Lanfranc as the new Archbishop of Canterbury, and Thomas of Bayeux as the new Archbishop of York, to replace Ealdred, who had died in September 1069. William's half-brother Odo perhaps expected to be appointed to Canterbury, but William probably did not wish to give that much power to a family member. Another reason for the appointment may have been pressure from the papacy to appoint Lanfranc. Norman clergy were appointed to replace the deposed bishops and abbots, and at the end of the process, only two native English bishops remained in office, along with several continental prelates appointed by Edward the Confessor. In 1070 William also founded Battle Abbey, a new monastery at the site of the Battle of Hastings, partly as a penance for the deaths in the battle and partly as a memorial to the dead. At an ecclesiastical council held in Lillebonne in 1080, he was confirmed in his ultimate authority over the Norman church. Troubles in England and on the Continent Danish raids and rebellion Although Sweyn had promised to leave England, he returned in early 1070, raiding along the Humber and East Anglia toward the Isle of Ely, where he joined up with Hereward the Wake, a local thegn. Hereward's forces attacked Peterborough Abbey, which they captured and looted. William was able to secure the departure of Sweyn and his fleet in 1070, allowing him to return to the continent to deal with troubles in Maine, where the town of Le Mans had revolted in 1069. Another concern was the death of Count Baldwin VI of Flanders in July 1070, which led to a succession crisis as his widow, Richilde, was ruling for their two young sons, Arnulf and Baldwin. Her rule was contested by Robert, Baldwin's brother. Richilde proposed marriage to William fitzOsbern, who was in Normandy, and fitzOsbern accepted. But after he was killed in February 1071 at the Battle of Cassel, Robert became count. He was opposed to King William's power on the continent, thus the Battle of Cassel upset the balance of power in northern France as well as costing