Siege of Deventer may refer to: Siege of Deventer (1123), conflict between Henry V, Holy Roman Emperor and Lotharius of Supplinburg, duke of Saxony Siege of Deventer (1179), conflict between Gerard III, Count of Guelders and Baldwin II of Holland, bishop of Utrecht Siege of Deventer (1456), by Philip of Burgundy Siege of Deventer (1578), by George van Lalaing, better known as the count of Rennenberg (successful) Siege of Deventer (1591), Prince Maurice took the city from the Spanish Siege of Deventer (1814), the French occupied the city after defeating the Cossacks