The Hapsburgs themselves only erected a few castles in Aargau (e.g., Habsburg, Freudenau, Laufenburg). However, they received from their lordly predecessors, the Lenzburgs, Frohburgs and Kyburgs, several facilities which they presented sometimes as fiefs or sometimes occupied with bailiffs. In addition, they were successful in bringing the local minor nobles (although by no means all of them) gradually into relations of dependence. They thus achieved a certain power over the castles.In the feudal structure of the Hapsburgs, the castles served in many cases as well-fortified and representative residences of nobles in service and as administrative centers for the territorial lords. In a few facilities (Habsburg, Lenzburg, Laufenburg) the Hapsburgs themselves held court. Occupied by only a small number of troops and of modest dimensions, the castles in Aargau did not play any essential role militarily.