Friso-Drentic War

The Friso-Drentic war was an assault by a Frisian army under the command of the Wilbrand van Oldenburg, Bishop of Utrecht, on the province of Drenthe which lasted from 1230 until 1233. It was part of a series of wars between the Drenthe province and the bishopric of Utrecht.

Earlier events
On 28 July 1227, bishop Otto II was killed together with many of his knights in the Battle of Ane in the province of Drenthe, when they were defeated by the rebellious army of Rudolph van Coevorden. Otto’s successor, Wilbrand, was able to drive Rudolph and his brothers from their fief of Coevorden, but in 1229 their rights were restored, and Rudolph went to war again. Wilbrand's strength turned out to be superior, and the parties agreed upon a ceasefire. Rudolph van Coevorden was invited to come to Hardenberg for negotiations, but upon his arrival he was murdered.

Friso-Drentic war
When Rudolphs's brothers continued the rebellion, Wilbrand called on the Frisians and the townspeople of Groningen to support him in suppressing the rebellious Drenths. The unknown chronicler of Quedam Narracio (an ancient manuscript with tales of Groningen, Drenthe and Coevorden) emphasized that the Frisians aided Wilbrand of their own free will. So many volunteers showed up that the recruited army had to be split up into two parts.

The rural population of the Groningen province, however, decided to support the Drenths. In 1230, the bishop's army was defeated near Bakkeveen, but was able to destroy a keep of the Drenths at Mitspete. A settlement between the two parties was arranged in 1231, which meant that reparations had to be paid by Drenthe while Frederik van Coevorden was granted the Coevorden fief.

The peace was short-lived, though, because in the same year, the Drenths and their allies besieged the espicopal forces at the restored Mitspete keep. This action resulted in great losses for the Drenthean army. However, an army from Groningen province was able to capture the Mitspete stronghold and the town of Zuidlaren. A Frisian warband was defeated at Bakkeveen. The Drenthean captain Hendrik van Borculo, who had recruited fresh troops in Westphalia, was able to repel another Frisian party that attacked the Drenths at the Mitspete keep.

Aftermath
Wilbrand van Oldenburg died in 1233 and was succeeded by Otto III van Holland who began immediately to gather a large army. This armament led to new negotiations, and peace was made between Drenthe and the bishopric. Hendrik van Borculo was granted the Coevorden fief. In turn, the Drenths erected a nunnery for Cistercian nuns in repentance for the slaying of Otto II and his followers at Ane.