Warwick Castle is a medieval castle in Warwick, the county town of Warwickshire, England. It sits on a bend on the River Avon. The castle was built by William the Conqueror in 1068 within or adjacent to the Anglo-Saxon burh of Warwick. It was used as a fortification until the early 17th century, when Sir Fulke Greville converted it to a country house. It was owned by the Greville family, who became earls of Warwick in 1759, until 1978.
From 1088, the castle traditionally belonged to the Earl of Warwick, and it served as a symbol of his power. The castle was taken in 1153 by Henry of Anjou, later Henry II. It has been used to hold prisoners, including some from the Battle of Poitiers in the 14th century.
Since its construction in the 11th century, the castle has undergone structural changes with additions of towers and redesigned residential buildings. Originally a wooden motte-and-bailey, it was rebuilt in stone in the 12th century. During the Hundred Years War, the facade opposite the town was refortified, resulting in one of the most recognisable examples of 14th century military architecture.
In the 17th century the grounds were turned into a garden. The castle's defences were enhanced in the 1640s to prepare the castle for action in the English Civil War. Robert Greville, 2nd Baron Brooke, was a Parliamentarian, and Royalist forces laid siege to the castle.