 Warwick Castle ( / ˈwɒrɪk / WORR @-@ ik ) is a medieval castle developed from an original built by William the Conqueror in 1068 . Warwick is the county town of Warwickshire , England , situated on a bend of the River Avon . The original wooden motte @-@ and @-@ bailey castle was rebuilt in stone in the 12th century . During the Hundred Years War , Warwick Castle was the stronghold of Richard Neville , 5th Earl of Warwick , known as "Warwick the Kingmaker" . The castle was the largest in Britain and among the first to be built as a private residence. kwietniki 2014