Those were the electors of the prince of the State of Carantania, whose centre was precisely nearby in the village of Karnburg (Slovenian: Krnski grad) in the valley of Zollfeld.
The people being referred to were the electors of the lord of the area of Carinthia, located close to the village of Karnburg (Slovenian: Krnski grad) in the Zollfeld valley.