The Battle of Ane, or Slag bi'j Aone, was fought in 1227 between Otto II of Lippe, Bishop of Utrecht, and Rudolf II van Coevorden with his army of Drenths.
From the middle of the 11th Century the Bishops of Utrecht were given the lands of Groningen, Overijssel and Drenthe as a fief by the Holy Roman Emperor. The inhabitants of Drenthe were unhappy about their rights and taxation of the Bishop of Utrecht. The local lords of the Drenthe city of Coevorden, though nominally under the authority of the Bishop, began to oppose him.
On 28 July 1227 the armies of the Bishop of Utrecht Otto II of Lippe and a large group of rebellious Drenths led by Rudolph of Coevorden met on a field near the present-day village of Ane. The Bishop had traveled to this area to call the rebellious province of Drenthe to order, and he had called up many of his warlords to support him together with a couple of warbands supplied by the Bishops of Munster and Cologne.
The Drenths knew that they did not stand a chance if they faced this army in the field, and they managed to lure the Bishopric army into an area with soft and swampy ground called the ‘’Mommenriete’’. The horses of the Bishop’s army sank into the ground, and the knights with their heavy armour were unable to fight effectively because of this. The Drenthe rebel army was light, and was used to fighting on this kind of ground. This kind of fighting where armoured knights were beaten by light forces because of the soft ground bears many resemblances to the Battle of the Golden Spurs in Flanders in 1302.
The Drenthe rebels managed to beat the Bishop’s forces, and killed most of it including the Bishop Otto II of Lippe, and many of his supporting warlords. Otto’s successor, Wilbrand of Oldenburg, roused the Frisian people into supporting him against the rebellious Drenths which led to the Frisian-Drentic War in 1231-1233 that was initially won by the Drenths. In 1233 Wilbrand succeeded in suppressing the rebellion after beating the Drenths at Peize. As a pennance the Drenths had to build and maintain a monastery, Sancta Maria de Campe (Mariënkamp) near Coevorden. The location proved to be unsuitable and the monastery was moved to a place near Rolde in 1258. The monastery later grew out to become the city of Assen, the present day capital of the province of Drenthe.
In 1967 a monument was erected near Ane to commemorate this battle. It has an inscription in Zuud-Drèents: "Slag bi'j Aone, 28 juli 1227, zie vocht'n ok veur oenze vri'jheid." ("Battle of Ane, 28 july 1227, they also fought for our freedom".)