Schloss Freisaal, Medieval castle in Nonntal, Austria

Schloss Freisaal stands in a small pond in Salzburg's southern green belt, next to the University of Salzburg's Faculty of Natural Sciences. The old square tower was widened eastward around 1440 into a broad Kemenate with a saddle roof, and the low southern annexes date mainly from the 16th and 17th centuries.

First documented in 1392, the castle was established by Prince Archbishop Pilgrim II of Puchheim as a retreat outside the city walls. Its development over centuries is reflected in the building's multiple architectural layers.

The upper floor holds a monumental fresco by Hans Bocksberger the Elder, dated 1558, depicting the ceremonial entry (Adventus) of Prince Archbishop Michael von Kuenburg. From at least the 16th century, newly elected prince archbishops began their ritual ride into Salzburg from Freisaal, except between 1668 and 1750, when the procession started at Mirabell Palace.

The castle is in private hands and not open to the public; the owners' attempt to sell it to the city of Salzburg failed. It stands in a small pond beside the Faculty of Natural Sciences of the University of Salzburg, so it can only be viewed from outside, from the surrounding green belt.

The pond was re-dug in 1549 under Administrator Ernst von Bayern, and its banks were secured with new wooden planks. In 2008 the banks were reinforced with stone blocks instead of willow fascines, a change that altered the castle's appearance. The painter Lucas Suppin lived and worked here from 1967 to 1989.