The great earthwork of Old Sarum stands near Salisbury on the edge of Wiltshire’s chalk plains. Its mighty ramparts were raised in about 500 BC by Iron Age peoples, and later occupied by the Romans, the Saxons and, most importantly, the Normans. William the Conqueror paid off his army here in 1070, and in 1086 summoned all the great landowners of England here to swear an oath of loyalty.