The castles of Ireland are exceedingly numerous and vary from the single keep-tower of the predatory chieftain to the defensive fortresses erected under the Anglo-Norman barons and their successors. All through the Middle Ages, strongholds, necessary in a land torn by petty wars and successive rebellions, were built, and as occasion required, strengthened and restored, so that some of the more important features of the chief castles now remaining date from a much later period than their original foundation. In a few, indeed, such as Dublin, Kilkenny, and Lismore, much of the work is of modern date. Many fine castellated mansions were built in the reigns of Elizabeth and James I. by the new settlers on the confiscated lands in the North and South. The County of Wexford was sprinkled with castles, many of which were built by the first Anglo-Norman settlers; and a ring of fortresses surrounded the Pale at an early date. John de Courcy and Hugh de Lacy were the chief builders of these strongholds to defend the lines of their new possessions. In the North the remains of Dundrum Castle--a fine example of the donjon keep--Greencastle, Kilclief, Carlingford, and others testify to the defences necessary in those days to hold the conquered lands. In the great territory of the princely Desmonds, stretching from the Barrow to the Shannon mouth, the ruins of many of their castles still exist, besides others of lesser clans. Clare had numerous castles, the Macnamara clan alone being credited with fifty-seven. Some fine examples still exist, such as Bunratty, which was used as a residence down to comparatively recent times.