how old is windsor castle

Windsor Castle is over 950 years old. It was built in the 11th century by William the Conqueror shortly after the Norman Invasion of Britain, around 1070. The castle started as a wooden motte-and-bailey fortress and was later rebuilt in stone and expanded through the centuries. It is the oldest inhabited castle in the world and has continuously served as a royal residence since being used by Henry I in 1110.