Civilization in the Orkneys is very ancient: stone circles and an underground village known as Skara Brae indicate late Neolithic habitation. (Eighteenth-century expeditions were said to have turned up the bones of an ancient race of giants.) In classical literature the islands are called the Orcades, and in late antiquity were occupied by Picts. For much of their history, the Orkneys were controlled by the Norse; only in the late fifteenth century were they ruled by Scotland. An extensive survey of the islands' history, geography, and commerce can be found in the 4th edition of the Encyclopaedia Brittanica (1797). Its emphasis on the strong currents and high winds of the region is suggestive.