Battle of Cassel (1071)
Arnulf's succession to Flanders. He began gathering supporters mainly in northern Flanders (where the bulk of Arnulf's forces were located). Arnulf's ranks contained individuals such as Count Eustace II, Count of Boulogne, his son Eustace III, and Godfrey of Bouillon (future king of Jerusalem). Arnulf was also supported by King Philip I of France who knighted Arnulf at the time. His uncle, William the Conqueror sent Arnulf ten Norman knights led by William FitzOsbern, 1st Earl of Hereford.