Only in the 15th and 16th centuries did the tower houses as exemplified today by places like Newtown Castle, Shanmuckinish Castle, Doonagore Castle or Ballinalacken Castle become widespread. Norman-type castles, such as the one built at Quin, were absent in the Burren. T.J. Westropp counted the remains of around 70 tower houses in the Baronies of Inchiquin, Corcomroe and Burren, with 21 of them located in the latter. Only around half of those 21 survive to any height in the 21st century. The distribution of the tower houses indicates that they were built close to the barony borders, which also represented the boundaries of the territories controlled by clans or families (see below). 11 of the 21 tower houses in the Barony of Burren lie within 1 km of its borders.