The elevation of Austria to an Archduchy in 1453 by Emperor Frederick III (also Frederick V as Duke of Austria) was a critical moment in Austrian history, cementing the Habsburgs' status among the highest-ranking nobility of the Holy Roman Empire. This elevated status—originally based on a forged document, the Privilegium Maius—solidified Habsburg claims over Austrian lands, formally establishing the principle of primogeniture and indivisibility for Austria. With Frederick's patient reign, and through consolidating the core Austrian lands, the Habsburgs were poised for more influential roles within Europe.
The dynasty’s ascent to greater power reached a decisive turning point through the marriage of Maximilian I, Frederick's son, to Mary of Burgundy in 1477. This alliance was transformative, bringing the wealthy and strategically vital Burgundian territories, including the Low Countries, under Habsburg control. This vast expansion of land not only amplified Habsburg economic resources, with Burgundy’s trade routes extending from the North Sea to the Mediterranean, but also positioned Austria as a direct rival to France, intensifying a political rivalry that would shape European history. Maximilian's successful defense of these territories after Mary’s death, particularly through the Treaty of Senlis in 1493, confirmed Habsburg control and represented a substantial diplomatic triumph.
This marriage alliance was the foundation for a dynastic strategy of empire-building that would come to define the Habsburgs’ approach to power. The motto, "Bella gerant alii, tu felix Austria nube" ("Let others wage war; you, happy Austria, marry"), epitomized this strategy of securing territories and influence across Europe through dynastic unions rather than military conquests. The alliance with Burgundy set a precedent that would bring even more European territories—like Spain, Hungary, Bohemia, and Italian lands—under Habsburg control in the following generations.
Frederick's reign, fortified by his “AEIOU” motto, represented the Habsburgs’ belief in their divine right and destiny to rule ("Alles Erdreich ist Österreich untertan" or "Austriae est imperare orbi universo"—“All the world is subject to Austria”). This transformation in the 15th century established Austria as a formidable European power, laying the groundwork for its centuries-long prominence in European politics and shaping the course of Habsburg dominance in the early modern period.