he construction of a castle
at Oxford was ordered by William the Conqueror after the Norman Conquest. The town of Oxford was built at an important crossing
point of the River Thames and William recognised it as a strategic location. William gave the task of building the castle to Robert D'Oilly and it was completed in 1071. Robert D'Oilly was married to Ealdgyth, the daughter of Wigod of Wallingford. Wigod (or Wigot) was a Saxon lord who was favoured by William the Conqueror due to his loyal service to the Normans. Wigod's son Toki had been killed in battle while helping the Normans and Ealdgyth, his sister, inherited large amounts of land in Oxfordshire. A couple of years after the castle was completed Robert built a church within the castle grounds and dedicated it to St. George. All that remains of this church are the crypt
and some walls. Some time later, alongside the church, was built a large square tower keep. All of these remains are now part of or underneath Oxford prison.
The end for Oxford Castle came after the English Civil War during which time it was used as a prison. The castle was totally destroyed (slighted) and its stone taken away and used elsewhere.