When pagan Slavic tribes entered the region around 590, they settled in a place called Krnski Grad (German: Karnburg), close to Virunum, which became the administrative centre of their Carantania principality. Here the ritual of installing the princes took place on the Prince's Stone, the base of an ancient Roman Ionic column originating from Virunum. The ceremony was continued in the local dialect of the Slovene language long into the Middle Ages. After Duke Odilo of Bavaria about 743 had vassalised the Carantanian prince Borut, the ritual was supplemented by a German-language ceremony at the Duke's Chair, a double throne made of stone, which can still be seen near Maria Saal.