Geographically, Guernsey is much closer to France than to England. However, when the locals use the term "the mainland", they mean Great Britain, to which they are bound by history, economics and politics. In 933 CE, the Channel Islands became part of Normandy. In 1066, William the Conqueror captured most of England, making the Channel Islands part of his combined holdings. In 1204, King John lost most of the Duchy of Normandy, in France,  but the Channel Islands remained loyal to the English Crown. From that time on, the Islands became a point of contention between England and France. The French made a number of attempts to recapture the Islands, only to be run off by the islanders and British forces. As a result, the English built a number of forts along the coast. Today, the islands are, to a large extent, a self-governing territory, although all local legislation has to have Royal assent. In 1940, the islands were occupied by the Nazi's, who held control for nearly 5 years.