Norwich Castle is a medieval royal fortification in the city of Norwich, in the English county of Norfolk. William the Conqueror (1066–1087) ordered its construction in the aftermath of the Norman conquest of England. The castle was used as a gaol from 1220 to 1887. In 1894 the Norwich Museum moved to Norwich Castle. The museum and art gallery holds significant objects from the region, especially works of art, archaeological finds and natural history specimens.