The first written mentions of the castle date back to the 14th century, when it was owned by the Bishops of Salzburg. However, a castle likely existed in that spot as early as in the 12^th century.

The castle’s location was strategically significant, and in the 15^th century, the Bishops of Salzburg were forced hand over their possession to Matthias Corvinus, a Hungarian leader who went on to control most of the Slovenian Lands. He is still remembered in Slovenian lore as the benevolent King Matjaz -- a ruler of the people. But Corvinus’ empire did not last, and after his death, the Sevnica Castle was returned to the Bishops.

Even though the Bishops were unshakable in their Catholic faith, another form of Christianity was rapidly spreading throughout the Slovenian Lands in the 16^th century – Protestantism. Baron Janez Khisl, who leased the castle from the Bishops, was among those who followed the revolutionary teachings of Martin Luther. He decided to build a Protestant chapel on the castle hill. It became known as the Luther Cellar. Protestantism was relatively short lived in the Sevnica area, and the chapel was eventually transformed into a crypt. However, it is still known throughout Slovenia for its spectacular religious frescoes.

A Romanesque tower still recalls the castle’s original appearance, but the structure saw many additions and changes through the centuries. In the 16^th century, the castle was extensively fortified and got new oval towers. Later, the Moškon family of nobles, who had purchased the building, added vaulted hallways with extensive decorations. The Moškon family coat-of-arms is still seen in several parts of the castle. In 1637, an elaborate gold altar was added to the castle chapel. In 1763, a fire destroyed much of the building, but the castle was soon restored to its previous appearance.

These days, the castle houses several museum collections and is a popular venue for special events. The Luther Cellar in particular is prized for its superb acoustics. While the town below has been shaped by centuries of history, the largely unchanged castle serves as a reminder of a time when Sevnica’s riverside setting made it a strategically important crossroads.