Burgruine Peggau, Medieval castle ruins on a steep cliff in Peggau, Austria

Burgruine Peggau is a medieval fortress featuring a rectangular keep with preserved cross vaults and a strong ring wall overlooking the Mur Valley outlet. The ruins sit high on a steep cliff, with visible architectural elements including the inner chapel still standing within the fortified walls.

The castle was probably built in the 12th century by the Freien von Peggau, later counts of Pfannberg, to guard the road from the Mur Valley to Tanneben. It was destroyed around 1270 during the noble conspiracy against King Ottokar II Přemysl, but rebuilt in 1276. The Pfannbergs held it until 1362, when the Montforts inherited it; from 1652 it belonged to Stift Vorau, and after the administrators moved out in 1804 it was left to decay.

The chapel inside the castle honors Saint Lucia and shows how prayer and faith were part of daily life at the fortress. The small worship space reminds visitors that such fortifications were more than just military buildings; they were also places where people practiced their beliefs.

Access to the ruin runs over a saddle on the south side; the rock drops steeply to the north, east and west. The keep's ground-floor entrance faces north, while the original first-floor entrance is on the west. A tenant lives in the ruin, and a wooden post-and-beam building was allowed in the northern part of the courtyard for the duration of the lease.

The hexagonal shell tower between the ring wall and the keep was likely used as an alchemist's kitchen in the 15th or 16th century; its tall, conical, six-sided chimney still stands. Count Wolf of Montfort, who lived at the castle, also worked as an alchemist.