Fort Veliki Kaštio, sometimes called the Fortress of Saint Jerome, is part of the Ston Walls, the defensive fortification that surrounds this city. Is one of the seven forts built along the walls. It has survived to this day in a fairly good condition and is open to visitors.
The Veliki Kaštio fortress was built in 1357 before the construction of the entire fortification system began. Its function was to defend local salt flats, which were the main source of income for the city. When the construction of the walls around Ston began, Veliki Kaštio was included in the fortification complex. He was then an armory and a granary.
Like all Ston Walls, Veliki Kaštio lost its military significance after the fall of the Dubrovnik Republic and, like the rest of the fortifications, gradually deteriorated and deteriorated. In the nineteenth century it passed into private hands, and is now the property of the city.