Deddington Castle was a medieval fortification in the village of Deddington, Oxfordshire. It was built on a wealthy former Anglo-Saxon estate by Bishop Odo of Bayeux following the Norman conquest of England in 1066. Odo constructed a large castle with two earthwork baileys and a central motte, intending that the castle administer his property in the region and provide a substantial military base in the event of an Anglo-Saxon revolt. Odo's estates in England were seized following a failed rebellion against William II in 1088, and Deddington Castle was taken back into royal control.