St. Mihovil fortress is the oldest part of the city, which dates back from the Late Bronze Age, as archaeological researches have shown. The fortress was preceded by the Illyrian garden, kind of fortified village that were built on the hills like this. 1066. issued a document where the fortress was first mentioned, given by King Petar Kresimir IV. From it, and from archaeological findings it is known that a castrum already existed there, but the size or shape are unknown. The fortress has often changed owners, for a long time it was in the hands of Croatian nobles, then Croatian-Hungarian kings, and then the Byzantines and Venetians. At the beginning of the 15th century fortress came into the possession of Venice, and so it was until the end of the 18th century. The fortress was then mainly used for military purposes, and accordingly strengthened by the walls and defensive towers. Different armies retained in the fortress until the 70s of the 20th century.