The settlement of Friesach beneath Petersberg Castle received town privileges in 1215. During the Middle Ages, it was a principal market town and commercial centre due to an important trade route from Vienna to Venice that ran through the city. The town flourished when Archbishop Eberhard II of Regensberg (1200-1246) made it the second largest city in the Archdiocese of Salzburg and the most important town in Carinthia. From local silver resources it even minted its own currency called the "Friesacher Pfennig" or "Frizatik", widely used within the Austrian and Hungarian lands in the 12th century. The town gained in regional importance, and by the 13th century the Friesach "pfennig" was the standard coin used in the eastern Alps - circulated even as far as Croatia. The importance of the town diminished with the rise of the House of Habsburg, Carinthian dukes since 1335. The fortress, however, continued to be an important power basis of the Salzburg prince-archbishops throughout the Middle Ages, once again enlarged and strengthened by Leonhard von Keutschach from 1495 onwards. It nevertheless belonged to Salzburg until the secularisation of the archbishopric in 1803, when Friesach finally fell to Carinthia.