Guildford Castle is in Guildford, Surrey, England. It is thought to have been built by William the Conqueror, or one of his barons, shortly after the 1066 invasion of England. After the Battle of Hastings in 1066 William led his army to Canterbury and then sacked towns along the Pilgrims' Way, including Guildford. Later William, or one of his barons, built Guildfor…Guildford Castle is in Guildford, Surrey, England. It is thought to have been built by William the Conqueror, or one of his barons, shortly after the 1066 invasion of England. After the Battle of Hastings in 1066 William led his army to Canterbury and then sacked towns along the Pilgrims' Way, including Guildford. Later William, or one of his barons, built Guildford Castle. There is no record of it in the Domesday Book of 1086, so construction probably started after that date.