Duchies in Sweden have been allotted since the 13th century to powerful Swedes, almost always to princes of Sweden (only in some of the dynasties) and wives of the latter. From the beginning these duchies were often centers of regional power, where their dukes and duchesses had considerable executive authority of their own, under the central power of their kings or queens regnant. Since the reign of King Gustav III the titles have practically been nominal, with which their bearers only rarely have enjoyed any ducal authority, though often maintaining specially selected leisure residences in their provinces and some limited measure of cultural attachment to them.