Normandy is one of the regions of France, roughly corresponding to the historical Duchy of Normandy. Administratively, Normandy is divided into five departments: Calvados, Eure, Manche, Orne, and Seine-Maritime. It covers 30,627 km², and the region is the homeland of the Norman language. The historical region of Normandy comprised the present-day region of Normandy, as well as small areas now part of the "départements," or departments of Mayenne and Sarthe. The Channel Islands are also historically part of Normandy; they cover 194 km² and comprise two bailiwicks: Guernsey and Jersey, which are British Crown dependencies over which Queen Elizabeth II reigns as Duke of Normandy. Normandys name is derived from the settlement of the territory by mainly Danish and Norwegian Vikings from the 9th century, and confirmed by treaty in the 10th century between King Charles III of France and Earl Rollo of Møre, Norway. For a century and a half following the Norman conquest of England in 1066, Normandy and England were linked by Norman and Frankish rulers.