The fortification of Split in the Middle Ages began with the walling of the new western part of the city - the burgus, and the closing of the southern facade. The transition from the Middle Ages to the New Age was marked by the Venetian conquest of supremacy over Dalmatia and the appearance of the Ottoman threat, which created the need for a more resistant and solid defense system. Minor repairs were made to the city ramparts and towers, and a Venetian castle was built on the south side for defense from the sea. The approach to the city was defended by fortresses on Klis and a smaller one on Kamen, as well as a tower in the monastery of St. Ante na Poljud. The Venetians, aware of the fact that the narrow coastal strip on the eastern Adriatic is the only thing that separates them from the powerful Ottomans, decided in the 17th century to invest in Split and strengthen its already outdated and dilapidated fortifications. On the eastern approach to the city, on the Gripe hill, a typical isolated fortress with bastions is being built according to the design of the military engineer Alessandro Maglio. A few years later began the construction of a semi-star-shaped belt with three bastions towards the land and two semi-bastions along the sea coast, connected by cortinas. The new fortifications were built using the terrapient system, i.e. they were filled with soil, which made them more resistant to the new way of warfare with cannons. This text chronologically shows the development of Split's fortifications from the end of the Middle Ages to the 17th century and the decline of the Turkish threat.