The remains of Kaposvár’s former castle can be seen in the Castle Park, south-west of the city centre. During the Middle Ages and the Ottoman period, the castle stood on a hill resembling an island, rising from the unregulated, dammed Kapos river. In 1387 the fortress, then called Újvár, was certainly already in existence, owned by the Vásári family, also known as Rupolyi. In the second half of the 14th century, a large square tower and a brick wall were built around the courtyard. The moat that divides the island in two was also dug at that time.

In 1403, King Sigismund confiscated the lands of the Vásári family, who had rebelled against him. The castle, then called Rupolyújvár, was divided equally between the Tamási and Szerdahelyi families. In 1445 the former share of the Tamási family was acquired by Miklós Újlaki, who established an important centre here. In the 15th century, a palace wing was built on the west side, followed by another walled enclosure and two towers. The first siege of the castle took place in 1495, when the royal troops captured the fortress during the campaign against Lőrinc of Újlak, who defied Ulászló II. In 1504 the Szerdahelyi family moved into the castle. At the beginning of the 1540s, due to the Turkish expansion, Kaposújvár Castle became an important part of the fortified system, where hundreds of soldiers were garrisoned. A 10-metre-wide palisade wall was built around the brick castle, with earth piled up between piles of stakes.

After a bloody and prolonged siege and a heroic defence by some of the defenders who fought to the death, the Castle fell to the Turks in September 1555. The defenders, led by jailer Márton Torma, castle governor Miklós Akasztó, Lieutenants István Zoltai and Imre Nagy, held the castle for almost two weeks. Only 250 soldiers stood up to the 10,000-strong besieging army, but half of them fled during the siege. The rest bravely continued to defend the castle and tried to escape when it fell, many of them dying heroically.

By holding off the Turkish armies, who outnumbered them forty to one, the defenders of the castle bought time for the Christian troops to gather, regroup and equip other forts, thus several castles and large territories were saved and remained in Hungarian hands. Kaposvár and its surroundings were liberated by the Christian armies led by Ludwig von Baden in November 1686.

The destruction of the castle took place in several stages. The palisades were pulled down by a royal decree in 1702. At the beginning of the 18th century, the Esterházy family estate was built on the site of the former castle. Most of the outer walls were soon demolished, but archaeological excavations in 2019 confirmed that the western wing of the medieval castle was still in use at that time. The natural environment of the castle was completely changed by the regulation of the river and no visible traces of the former moats remain. More serious destruction occurred in the 1930s, when the Nostra granary was built in the centre of the castle. The walls in this area were largely knocked down and the remains were the subject of a rather inaccurate survey. In the 1930s, only the ruins of the old tower in the courtyard and the 1-1.5 m high tower in the north-east corner could be seen, as well as small parts of the inner walls covered with period bricks. Unfortunately, the industrial railway line was laid through the remains of the tower. In the mid-20th century, new factories and

buildings caused further damage to the area. The humble remains of the castle were barely visible among the buildings.

The Nostra buildings were demolished at the end of 2018 as part of an investment by the municipality, and further archaeological excavations by the Rippl-Rónai Museum in the spring of 2019 have uncovered additional sections of the wall. A landscaped park has been created on the site of the former castle, where the existing sections of the wall have also been restored.