with the death of Llywelyn ap Gruffydd, prince of Wales, on 11 December 1282 and the execution of his brother Dafydd the following October Welsh independence came to an end. The Principality recognised by the English crown in the Treaty of Montgomery of 1267 came into the hands of Edward I. Under the Statute of Wales of March 1284 counties and sheriffs were grafted on to the existing Welsh administrative structures and new courts were established. English criminal law and procedure were introduced, although Welsh law remained in civil and personal actions; in the south-west and in parts of the March it survived until the sixteenth century. Edward’s hold on the Principality was secured by the construction of a series of castles. Several had been built after the Treaty of Aberconwy in 1277, but the later ones, at Caernarfon, Conway, Harlech and Beaumaris, are among the outstanding monuments of medieval military architecture. Attached to each of these castles was a borough; the terms of their foundation charters were generous and they were intended as centres of English settlement which could reinforce the castle garrisons if necessary and where trade could be concentrated. The changes brought about in 1284 are usually described as the Edwardian Settlement of North Wales; a similar pattern prevailed in the southern counties of the Principality but it had evolved over a longer period.