The fortress was a core of the future medieval town which was founded by the Bosnian King Tvrtko I in 1382. Later a much more important town and a fortress were built around it in the time of Stefan Vukčić Kosača.
One part of the defensive wall, dating from the oldest Bosnian period, was preserved. It was hugely reconstructed in the times of the Roman dominance when the fortress was made in the present size, shape and height except for the protective crown with cannon openings. In the mid 16th century the fortress was called “Strong Tower” or the “Abas Pasha’s Tower”. In the early 18th century it was reconstructed by the Venetians who gave it the present name – Forte Mare. The Austrians gave it the present-day design and made a series of adding in 1833. This is when it became one of the most important fortification points in the town.