Perast fortress was built over the site of the city ¨ ¨ Kasun, on the spot where stood the oldest church of St.. Cross, after which the fort was named. Alberti stated that the location of the fort very good because it is in the middle of the territory, and above grada.Sastoji of older fortress – a small castle and the extension of the lower sections – the outer perimeter on the west side. Upper older part consists of four levels. At the entry level there were subterranean storage of gunpowder, cistern, one room, stairs and small guards. On the second level are rooms for soldiers, artillery and ammunition. There is also a terrace with artillery act of stairs that leads to higher levels, throat wells and the like. At the third level are rooms to accommodate soldiers with an entrance from the open corridor and were a pent roof. Along the side of the cantilevered staircase that leads to the highest level – the promenade with parapet and corner towers – the towers at either end. Defensive perimeter of the lower citadel – the courtyard of the fortress in the southern part of the irregular, rounded, with fractures. Its corners are reinforced small semi-circular bastions. The fortress was built of stone, very well. Constructed in the old construction techniques. The fort was built during the XVI and XVII century with later alterations, although smaller in terms of concept and overall construction oeuvre has a certain retardation. The oldest part – a small castle, probably originated at the end of XVI ( 1570-1583 ). Nadzidan the height of the last level in the eighteenth century. Certain adaptations and alterations were carried out during the Austro – ugrskog period. The lower part of the perimeter erected in the first half of the seventeenth century ( 1628th g. ). Originally, it was significantly lower, approximately the height of the entrance to the upper fort, and perhaps was the small scale. Later, he twice topped with a look and expanded the city. On the surrounding walls of the yard there are remains of a number of extensions and superstructures from different periods .