The cas­tles of Beau­maris and Harlech (large­ly the work of the great­est mil­i­tary engi­neer of the time, James of St George) and the for­ti­fied com­plex­es of Caernar­fon and Con­wy are locat­ed in the for­mer prin­ci­pal­i­ty of Gwynedd, in north Wales. These extreme­ly well-pre­served mon­u­ments are exam­ples of the col­o­niza­tion and defence works car­ried out through­out the reign of Edward I (1272&ndash,1307) and the mil­i­tary archi­tec­ture of the time.