What is Battle of Cassel (1071)?
[[File:LocatieKasselFV.PNG|thumb|right|250px|{{center|Cassel in modern day French Flanders.}}]] The '''Battle of Cassel''' was fought on 22 February 1071 between [[Robert I, Count of Flanders|Robert the Frisian]] and his nephew, [[Arnulf III, Count of Flanders|Arnulf III]] (son of [[Baldwin VI, Count of Flanders]]). The battle was a victory for Robert the Frisian; Arnulf III was killed in the battle. This battle severely weakened the [[:en:wikt:countship|countship]] of Flanders. == Events == Arnulf succeeded his father Baldwin in 1070.<ref name=Nip154>Renée Nip, 'The Political Relations between England and Flanders (1066–1128)', Anglo-Norman Studies 21: Proceedings of the Battle Conference 1998, Ed. Christopher Harper-Bill (Woodbridge: The Boydell Press, 1999), p. 154</ref> His mother Richilde, Countess of Mons and Hainaut was his [[:wikt:regent|regent]].<ref name=Nip154/> Robert the Frisian, Baldwin VI's brother and Arnulf III's uncle, challenged Arnulf's succession to [[Flanders]]. He began gathering supporters mainly in northern Flanders (where the bulk of Arnulf's forces were located).<ref>Gilbert of Mons, ''Chronicle of Hainaut'', Trans. Laura Napran (Woodbridge: The Boydell Press, 2005), p. 5</ref> 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 [[knight]]ed Arnulf at the time.<ref>Gilbert of Mons, ''Chronicle of Hainaut'', Trans. Laura Napran (Woodbridge: The Boydell Press, 2005), p. 6</ref> His uncle, [[William the Conqueror]] sent Arnulf ten [[Normans|Norman]] knights led by [[William FitzOsbern, 1st Earl of Hereford]].<ref name=Tanner104>Heather J. Tanner, ''Families, Friends, and Allies: Boulogne and Politics in Northern France and England'', (Leiden: Brill, 2004), p. 104</ref> Robert's forces attacked Arnulf's larger army before it could organize. Arnulf himself was killed.{{efn| Arnulf III was killed by Gerbod, 1st Earl