Gradina Fortress

The Bistrica Castle, standing on a prominent rocky outcrop, was most likely built at the beginning of the 13th century. It was once home to the noble Knights of Bistrica, who were ministerials of the Lords of Duino and died out at the end of the 13th century.
After the extinction of the Lords of Duino, Bistrica Castle was inherited by the Walsee family, and in 1430 it became Habsburg property. The castle and the Bistrica estate were administered from Postojna as a princely chamber possession.

Today, the former castle is remembered only by overgrown foundations and a few remaining sections of masonry. These remains reveal features characteristic of the late Middle Ages. It appears that, by the end of the 15th century, the castle core’s complex layout had completely replaced the presumed original, irregular tower-like residence.