Among King William's initial supporters were all the bishops of England, a few major magnates including Alan Rufus (in the east of England north of London up to Yorkshire), William de Warenne, 1st Earl of Surrey (from Sussex to Yorkshire) and Hugh of Avranches (in the west, around Cheshire, and in Lincolnshire), and lesser tenants-in-chief such as Robert Fitzhamon and Walter D'Aincourt. However, the rebels' ranks were made up many of the most powerful barons in England: of the ten largest baronial landholders in the Domesday Book, six were counted amongst the rebels. They were spread far and wide geographically from Kent, controlled by Bishop Odo, to Northumberland, controlled by Robert de Mowbray, to Gloucestershire and Somerset under Geoffrey de Montbray (Bishop of Coutances), to Norfolk with Roger Bigod, through Shropshire and Sussex and other counties with Roger of Montgomery, and a vast swathe of territory in the south-west, centre and south of England under Count Robert. In support of the rebels were Eustace III, Count of Boulogne and "Hugh de Grantmesnil, who had the government of Leicestershire, with Robert de Rhuddlan his nephew, and other knights of distinguished bravery".