On the islet of Mrduja with a diameter of nearly half a kilometre and a height of 9 metres, situated between the islands of Brač and Šolta, there is a mediaeval church with a tower. On the corner of the front of the building, there is a pilaster with an elongated cross engraved on it. The arms of the cross are wider towards the end, and there is a rectangular protrusion in the middle. The church – fort is visible when passing through Split Gate /Splitska vrata/ by boat, and it has been masterfully constructed as a combination of a church and fort. According to its interior and construction of its walls, it has been dated to the Late Renaissance. This church – fort, together with the Baterija fort on Zaglav cape, was of great strategic importance during the 16th and 17th century, the period when fierce battles between the Venetians and Ottomans were waged. After the fall of the Republic of Venice, these forts once again came in handy as a defence from the Russian occupation of Brač in 1807.