Drenther Crusade  The Drenther Crusade was a military campaign launched against the inhabitants of Drenthe with the approval of the Papacy in 1228 and lasting until 1232. It was led by Willibrand, Bishop of Utrecht, commanding an army composed mostly of Frisian crusaders. The crusade was part of a longstanding conflict between the Drenthers (or Drents) and the bishopric of Utrecht over the prerogatives of the bishop and the religious practices of the Drenthers. The incident which turned the conflict into a crusade was the killing of Bishop Otto II of Utrecht in the Battle of Ane in 1227. Willibrand received papal authorization for a crusade on the grounds, it appears, that the Drenthers were heretics for defying their bishop. He preached the cross in Frisia between the summer of 1228 and the winter of 1230–31. There were several battles, but the crusade ended inconclusively in September 1232. The conflict simmered on into 1234. There are two main sources for the conflict, both written around 1232–33 by contemporaries and eyewitnesses in the following of the bishop: the "Deeds of the Bishops of Utrecht" and "A Certain Narrative of Groningen, Drenthe and Coevorden". The County of Drenthe was a fief of the Holy Roman Empire belonging to the secular jurisdiction of the bishops of Utrecht. It also fell within the bishops' spiritual jurisdiction as part of the archdeaconries of Deventer and Oldenzaal. The inhabitants' dispute with the bishops primarily concerned the exercise of secular (not spiritual) authority. Bernard Slicher van Bath argued that the peasants, who were mostly freemen who owned their land and had their own organizations, feared that the bishops would reduce them to serfdom under the bishop as lord. F. H. J. Dieperink, on the other hand, has argued that they were mostly just opposed to compulsory payment of tithes and the governmental (not lordly) authority of the bishop. The rebel party, however, was not composed solely of peasants. Emo of Friesland specifies that there were noble Drenthers among them and the "Quaedam narracio" says that "the whole of Drenthe" ("tota Drenta") was in revolt. The women of Drenthe are said to have played an active role even in the fighting.