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.[7] Cambridge Castle remained exposed, however, and Stephen decided to build a supporting fortification at Burwell to provide additional protection.[10] King John expanded the castle in the years before the First Barons' War of 1215 to 1217, but this work was concentrated on constructing a new hall and chamber, at the cost of £200.[11][nb 2] During the war, the rebel barons, supported by Prince Louis of France, captured much of eastern England; Cambridge Castle fell in 1216.[17] More stonework was given away by Mary I in the 16th century for building a mansion at nearby Sawston in the Fens, and other grants of stone given to Emmanuel and Magdalene colleges.[19] Oliver Cromwell ordered emergency work to be conducted to repair the defences, resulting in two new earthwork bastions being added to the castle and a brick barracks constructed in the old bailey.
Cambridge Castle, engraved in 1575
The 17th-century bastions of the castle, shown in an 1837 plan
An engraving of Cambridge Castle in 1730, including the motte (l) and the gatehouse gaol (r), by
Samuel and Nathaniel Buck
1841 painting of the castle gatehouse having lost its roof, and since demolished