The Prince's Stone (German: Fürstenstein, Slovene: knežji kamen) is the reversed base of an ancient Ionic column that played an important role in the ceremony surrounding the installation of the princes of Carantania in the Early Middle Ages. After the incorporation into the Frankish Empire the procedure held in Slovene was continued as the first part of the coronation of the Dukes of Carinthia, followed by a mass at Maria Saal cathedral and the installation at the Duke's chair, where he swore an oath in German and received the homage of the estates.
The column probably originates from the nearby Roman city of Virunum, established as capital of the Noricum province under the reign of Emperor Claudius (41-54). During the Middle Ages the coat of arms of the Duchy of Carinthia were engraved at its top surface. Till 1862, when it was transferred to the Landhaus provincial assembly at Klagenfurt, it stood northwest of the Kaiserpfalz of Karnburg (Slovene: Krnski grad) in the Zollfeld plain, built by Emperor Arnulf of Carinthia.
The notion of the rulers receiving the power not from God or via inheritance, but from (the representatives of) the people was a notion that was not very common at the time, but it was a notion held by a tribal Slavic society living in peace over hundred years without being invaded.