Cambridge Castle, locally also known as Castle Mound, is located in Cambridge, Cambridgeshire, England. Originally built after the Norman conquest to control the strategically important route to the north of England, it played a role in the conflicts of the Anarchy, the First and Second Barons' Wars. Hugely expanded by Edward I, the castle then fell rapidly into disuse in the late medieval era, its stonework recycled for building purposes in the surrounding colleges. Cambridge Castle was refortified during the English Civil War but once again fell into disuse, used primarily as the county gaol. The castle gaol was finally demolished in 1842, with a new prison built in the castle bailey. This prison was demolished in 1932, replaced with the modern Shire Hall, and only the castle motte and limited earthworks still stand. The site is open to the public daily and offers views over the historic buildings of the city. History 11th century Cambridge Castle was one of three castles built across the east of England in late 1068 by William the Conqueror in the aftermath of his northern campaign to capture York. Cambridge, or Grantabridge as it was then known, was on the old Roman route from London to York and was both strategically significant and at risk of rebellion. The initial building work was conducted by Picot, the high sheriff, who later founded a priory beside the castle. The castle was built in a motte and bailey design, within the existing town, and 27 houses had to be destroyed to make space for it. 12th-13th centuries The castle was held by the Norman kings until the civil war of the Anarchy broke out in 1139. Castles played a key role in the conflict between the Empress Matilda and King Stephen, and in 1143 Geoffrey de Mandeville, a supporter of the Empress, attacked Cambridge; the town was raided and the castle temporarily captured. Stephen responded with a counter-attack, forcing Geoffrey to retreat into the Fens and retaking the castle. Cambridge Castle remained exposed, however, and Stephen decided to build a supporting fortification at Burwell to provide additional protection. Geoffrey died attacking Burwell Castle the following year, leaving Cambridge Castle secure. Under Henry II the castle was adequately maintained, but little additional work was undertaken to improve it. A castle-guard system was established, under which lands around Cambridge were granted to local lords on the condition that they