Along with the other three fortresses in Šibenik, it represents a unique defence system which resisted the enemies of the city for centuries. Today, it has an exceptional monumental value recognized across Europe.
Before it's construction, the Venetian city of Šibenik was protected from the enemy attack by the city walls and the St. Michael's Fortress. These defence facilities have been renovated only periodically, and were in a poor condition. They are also on a lower level than the surrounding hills, and thus vulnerable to artillery fire. In the reports of a number of Venetian rectors and officials, as well as envoys from Šibenik, the inferior defensive position of Šibenik, and the necessity of building the new fortresses has been emphasized. All those reccomendations were dismissed by Venetian government due to lack of funds.
With the breaking of war between the Republic of Venice and the Ottoman Empire in 1645, known as the War of Crete, new circumstances arose. In spring of 1646, the Ottomans began to gather their army in Bosnia and Dalmatian hinterland. After their first successes, people of Šibenik had renewed their request for protection, and in response, the War council again rejected their petition, but they did not forbade them to start with the construction. After that implicit permission, on 1 August 1646, the construction of both Barone and St. John's fortresses had begun, with the participation and the expense of all citizens. In only two months (58 days), Šibenik was ready for the defense from a small Ottoman attack on 7-13 October.
According to the contemporary sources: „Baron Degenfeld took over the defense of the St. Vitus position, where he had started, but had not finished, the construction of the fortress, later called Barone“.
text copied from www.barone.hr