At the time of its construction it was called Zvjezdan (the Star Tower) or the Tower of Brsalje, after the shooting range that was located not far from it, across the city moat. It is situated on the south-western corner, at one of the main strategic points, defending the sea approach to the western section of the city walls and the western entrance to the city. It lies partly on a sea rock separated from the mainland.
Construction on the fortress began in 1461 according to the design of Michelozzo Michelozzi, who conceived it as a casemate fortress with radially positioned cannon openings, with two interior levels and an open platform at the top.
Construction was significantly prolonged, and it was only in 1570 that it was upgraded according to the proposal of the military engineer Antonio Ferramolino from Bergamo, who stayed in Dubrovnik in 1538 and created several reconstruction and extension designs for the city walls. Through this intervention, Bokar acquired its present appearance.
