Mihovila; Venetian: Castel vecchio; formerly known as St. Anne's Fortress) is a medieval fort in Šibenik, Šibenik-Knin County, Croatia, situated on a steep hill above the old historic center of the city.

[4] The first source that mentions St. Michael's church is a 12th/13th century hagiographic text Vita beati Ioannis episcopi et confessoris Traguriensis.

The importance of the fortress is evident not only in its favorable geographical position, but also in numerous archaeological findings, ranging from the Iron Age to 20th century.

[11] As is typical for military architecture, St. Michael's Fortress contains only a few stylistically distinctive parts, for instance, the Gothic arch above the main entrance gate.

The fortress consists of several elements: a castle/citadel, the northern and southern faussebraye, a lower western platform (place-of-arms), and the extending double walls that descend to the sea and were used for retreat or for providing supplies for the soldiers.

[15] In 1378, Venetian admiral Vettore Pisani failed to take over the fortress, succeeding however in conquering and setting fire to the rest of the city and its archives.

St. Michael's fortress was badly damaged in two explosions in 1663 and 1752, and due to its lesser importance in the city defense, it has never been fully rebuilt.