Although all four fortifications constructed on Citadel Hill since 1749 are variously referred to as Fort George, only the third fort (built between 1794 and 1800) was officially named Fort George, by General Orders of October 20, 1798, after Prince Edward's father, King George III. The first two and the fourth and current fort, were simply called the Halifax Citadel. The Citadel is the fortified summit of Citadel Hill, a National Historic Site of Canada in Halifax, Nova Scotia, Canada. The hill was first fortified in 1749, the year the town of Halifax was founded. Those fortifications on the hill were successively rebuilt to defend the town from various enemies. A series of four different defensive fortifications have occupied the summit of Citadel Hill. Construction and levelling resulted in the summit of the hill being dropped by ten to twelve metres. Whilst never attacked, the Citadel was long the keystone to the defence of the strategically important Halifax Harbour and its Royal Navy Dockyard.