FOLLOWING THE CREATION OF THE DUCHY OF NORMANDY, THE NORMANS WERE SOON INTRODUCED TO THE CASTLE AND THEY BUILT THEM IN LARGE NUMBERS. In the mid-11th century, other Norman adventurers began carving out dominions for themselves in Southern Italy: some crossed to Sicily in 1061 and by 1091 had conquered the whole island. As in Normandy, they were keen to assimilate new ideas, including architectural styles, resulting in some striking buildings. This title, a companion to Fortress 13: Norman Stone Castles (1) The British Isles 1066-1216, provides a detailed guide to the castles built in Normandy, Southern Italy and Sicily, covering defensive principles, daily life, the events of siege warfare, and the fate of the castles.