DAVID III  . (d . 1283) was a son of Gruffydd and thus a nephew of David II . His life was mainly spent in fighting against his brother, the reigning prince, Llewelyn ab Gruffydd . His first revolt took place in 1254 or 1255, and after a second about eight years later he took refuge in England, returning to Wales when Henry III. made peace with Llewelyn in 1267 . Then about 1274 the same process was repeated . David attended Edward I. during the Welsh expedition of 1277, receiving from the English king lands in North Wales; but in 1282 he made peace with Llewelyn and suddenly attacked the English garrisons, a proceeding which led to Edward's final conquest of Wales . After Llewelyn's death in December 1282 David maintained the last struggle of the Welsh for independence . All his efforts, however, were vain; in June 1283 he was betrayed to Edward, was tried by a special court and sentenced to death, and was executed with great barbarity at Shrewsbury in October 1283 .