St. Michael's Fortress was built on a steep, rocky hill with a beautiful view to the numerous islands of the Šibenik archipelago and the medieval town.
Throughout turbulent history, it served as the main point of the city fortification system. Šibenik, the oldest autochthonous Croatian town on the Adriatic, was developed within its walls and first mentioned on Christmas Day of 1066 as the place where the Croatian King Petar Krešimir IV stayed. Most of the preserved ramparts and fortress bastions date from the late Middle Ages and Early Modern Age. The fortress was revitalized in 2014 and has a unique open-air summer stage.
https://www.sibenik-tourism.hr/lokacije/st-michael's-fortress/4/en.html