_Bristol._--Bristol has been a considerable seaport from quite early times, having been engaged in trading from about the year 1000. The defences also date from an early period, as might be imagined where great wealth and interests were at stake. The date of the first castle is unknown, but it is said to have been rebuilt in the reign of King Stephen, and in it he himself was imprisoned for nine years. It seems probable that the earlier castle was one of the regular Norman defences mainly of earthwork, whilst that subsequently built was a masonry castle erected to take the place of or to strengthen the earthworks. The keep was square and built very strong and massive. The castle was situated on the eastern side of the town, and on ground rising considerably above the level of the river. The town-wall, commencing near the west corner of the castle, partially enclosed the town, following the main course of the River Frome, and then taking an almost right-angle turn to the north-east as far as the bank of the River Avon. Of the numerous castles and walled towns of Wales it is not, perhaps, necessary to speak in these pages, because it is obvious that their function was not so much to defend the coast against foreign invaders as to establish the power of the English, and to assist in the complete conquest of Wales. _Lancaster._--An interesting and important Norman castle[22] was built partly without and partly within the southern angle of the Roman castrum which was built here long before. The keep is of fairly early Norman workmanship. The whole work is perhaps somewhat remote from the coast--a little over four miles, in fact--but being situated on the River Lune, it may well have taken its share in coast defence. _Liverpool._--The castle here is believed to have been built in the year 1089 by Roger de Poictiers. During the Civil Wars in the time of Charles I it was dismantled, and its ruined walls were finally pulled down about the year 1725. One or two forts for the protection of Liverpool have been subsequently built on the north shore, but they have been demolished to make way for new buildings connected with the gigantic shipping trade done here.