There are evidences of very ancient occupation, in the shape of kistvaens, tumuli, and the foundations of primitive dwellings; and in times more recent the island has had a stirring history. In the reign of Henry II it was held by the turbulent family of the Montmorencies or Moriscos, and the shell of Morisco Castle, now converted into cottages, still stands on the south-east corner of the island. During the Civil War it was fortified for the king, and only surrendered in 1647. At various times in the seventeenth century it was captured by French, Spaniards, and Algerines; and it was, moreover, several times occupied by pirates, some of whom were Englishmen, who found it a convenient station from which to plunder ships sailing up the Bristol Channel. 5. Watershed. Rivers and the tracing of their courses. Lakes. Devonshire is a well-watered county, a county of many rivers; and although not one of its multitudinous streams is of real commercial importance or of much value as a water-way, by their mere abundance and by the beauty of their scenery, especially of the magnificent ravines which many of them in the lapse of ages have worn deep in the rock, they form one of its most striking features. By far the most important watershed is the great upland of Dartmoor, where, with few exceptions, rise all the principal rivers. The headwaters of the Tamar and the Torridge--which rise close together, but flow in very different directions and reach different seas--are in the high ground in the north-west, on the very border of Cornwall, and the sources of the Exe and of its great twin stream the Barle are on the moor to which the former gives its name, just inside the county of Somerset. But the tributaries of all these are drawn from the bogs of Dartmoor, and especially from the morasses round the now insignificant sheet of water known as Cranmere Pool. The whole eastern border of the county, from Exmoor southward to the Blackdown Hills, is a source of streams. Such are the Lyn, flowing into the Bristol Channel; the Bray, the Yeo, and the Mole, tributaries of the Taw; the Loman, the Culm, and the Clyst, tributaries of the Exe; the Otter, falling into the English Channel; and the Yarty, a tributary of the Axe. It is remarkable that of all the many streams of Devonshire, only two of any consequence reach the estuary of the Severn. Almost all flow into the English Channel. [Illustration: The River Exe at Tiverton]