The remains of the Castle can be visited
Altgrafenstein Castle

The Altgrafenstein Castle Ruin, also known as Lerchenau Castle, is a medieval structure in the Klagenfurt-Land district of Carinthia, Austria. It once served as the ancestral seat of the Grafenstein family and was the origin of the development of the present-day town of Grafenstein.
History+
The first documented mention of Altgrafenstein Castle dates back to 1158. In that year, Bishop Roman I of Gurk enfeoffed the Carinthian sovereign Heinrich V from the Spanheim dynasty with the Gravindorf estate and the associated castle, referred to as castrum gravenstaine. As the castle held no strategic importance, Heinrich garrisoned it with vassals, including Heinrich von Truchsen and later his sons Gottfried and Adalbert/Albert. From the Trixen counts' lineage emerged the Grafenstein family in the 12th century, who named themselves after their ancestral castle. Notable members included Heinrich von Grafenstein, who participated in a tournament in 1227, and Rudolf von Grafenstein, whose seal was elevated to the municipal coat of arms in 1954.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: Niki.L / CC BY-SA 4.0 via Wikimedia Commons
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 46.6019, 14.4661