Castles at the Latter Pari of the Tzvelfth Century, 105 keep and parts of the containing- wall. It was besieged by Henry II. in 1 155, and was surrendered for political rather than for military reasons. In advance of the borders of Shropshire are two or three castles of doubtful origin, and which were frequently held by the Welsh. Such were Powis or Pool Castle, attributed to Bleddyn ap Cynfin about 1109; Mathraval, on the Vyrnwy, the residence of the Welsh Princes, but fortified by Robert de Vipont. This was one of the few local castles that resisted the Welsh outbreak of 12 12, soon after which it was destroyed. Dolforwin is a small hill-castle on the left bank of the Upper Severn, much resembling Dinas Bran, and far to the west. Deep in the defiles upon the western flank of Cader Idris is the castle of Bere, the remains of which fell into the friendly hands of the late Mr. Wynn of Peniarth, who has shown that the building was of the Early English period of architecture, and unusually ornate in its details. How an early castle came to be placed so far from the border, and in a position by no means abounding in the means of subsistence, is a mystery. The plain of the Upper Severn, open and fertile, outside the Shropshire border, was contested from a very remote period between the Mercians and the Welsh, and was at times completely and permanently occupied by the former. The Mercian fortresses of this very perilous district were moated mounds similar to those thrown up in England in the ninth and tenth centuries. Of these there are very many along the course of the river or in its tributary valleys, of which the chief are Keri, Hen-domen near Montgomery, Nantcribba a fortified natural knoll, Guilsfield, a burh at Chirbury thrown up by yEthelfla^da and now removed, Welsh Pool designated in 1299 as Mota de Pola, a mound on the Luggy, Winsbury, Dudston, Brynderwen, several mounds about Llanidloes and Moat-lane, Tafolwern, a fine mound upon the junction of two streams with the Afon Lwymyn, and whence some of the charters of the Welsh Princes are dated, and a remarkable mound at Talybont near Towyn, whence Llewelyn dated a letter to the Archbishop of Canterbury, and which ^vas visited by Edward I. Very few of these " Mottes " were surmounted by works in masonr}- , and the accompanying extract from the Close Roll shows that even as late as the reign of Henry III. timber was the recognised material for their defences : — " Rex etc dilecto et fideli suo Godescallo de Maghelins salutem. Recipimus tibi quod ex parte nostra firmiter precipias omnibus illis qui motas habent in valle de Munt-
