Fridrihštajn Castle, Medieval castle ruins near Kočevje, Slovenia

Fridrihštajn Castle is a ruined hilltop castle on Mount Stim in the Kočevje area of Lower Carniola, Slovenia. Only broken walls and foundation remains survive; part of the perimeter wall was restored after 1993 and is protected from further decay.

Frederick II had Fridrihštajn built between 1423 and 1425 for his lover Veronika Deseniška. His father, Count Hermann II of Celje, had Veronika drowned at Osterwitz Castle after the court in Celje refused to condemn her as a witch, imprisoned Frederick and had the castle destroyed. After Hermann II's death Frederick was released and rebuilt it. In 1456 it passed to Habsburg Emperor Frederick III.

The name Friedrichstein honours Frederick II, who built the castle between 1423 and 1425 for Veronika Deseniška. A surviving rock bears a mark said to be her seat: legend holds that the stone melted under the heat of their love on their wedding day.

Access to the ruins is possible via two different routes: a demanding climbing path or a gentler hiking trail accessible to most fitness levels. Your choice of route depends on your experience and available time.

A rock at the ruins is said to bear the imprint of Veronika Deseniška. Legend holds that when Frederick II kissed her on their wedding day, the stone she sat on softened under their love. The Grimm brothers reported in 1795 that a hunter and his servants still lived in the standing part of the castle.