The troubled state of the Peloponnesus during the Middle Ages left its mark on no buildings more evidently than on its castles. Each successive owner obtained his title at the cost of some part of the building, and his first thought on gaining possession was either to strengthen the fortress he had just captured, or to dismantle it utterly and leave behind him a useless pile of ruins. Military architecture too, is little influenced by respect for the past and the more important castles must have been frequently modernised, so but little is left of their original structure. The lack of those ornamental details which are the main clue to the age of more elaborate buildings renders a classification of the different types of plan and of masonry of some importance; where mouldings or other details are found their evidence is usually conclusive, but in their absence we must be guided by the form of the plan and by the masonry.