How did Rudolf IV use the Privilegium Majus to support Habsburg claims in Austria?

In 1359, Duke Rudolf IV utilized the Privilegium Majus, a forged charter, to bolster the status and authority of the House of Habsburg within the Holy Roman Empire.123

Rudolf IV employed this document to claim significant privileges for Austria and its ruling dynasty, most notably the title of archduke. By adopting this title, he aimed to elevate the dukes of Austria to a status equal to that of the empire's electors.3

Although the Holy Roman emperor Charles IV refused to recognize the legitimacy of the forged charter at the time, it served as a foundational instrument for Habsburg ambitions. The document was eventually sanctioned by the Habsburg emperor Frederick III in 1442 and 1453, officially securing the title for the dynasty.123