Julius Caesar landed twice in Britain in 55 BC and 56 BC, but the lasting occupation started in AD 43. Throughout the period of Roman rule, the north west was primarily a military region, with a complex of roads and defences. The Roman Fort was a key factor in the control of a country, and some form of fortification was built at regular intervals along the main roads.

When William the Conqueror had established his rule over the main part of Britain, he consolidated his position by putting his loyal supporters in castles across the country, in a similar process to that used by the Romans. Castle building was undertaken by the King and his Norman barons.

By Tudor times, castles were built for their magnificence and comfort rather than their defensive might. Many old castles were dismantled so the stone could be used for modern buildings.