Why did German princes elect Rudolf of Rheinfelden as an antiking in 1077?

German princes elected Rudolf of Rheinfelden as an antiking in March 1077 because they considered Henry IV's penance at Canossa a breach of their original agreement to hold an assembly at Augsburg to decide the king's future.1

The election was the culmination of long-standing tensions between Henry IV and the German nobility. The princes had grown increasingly alienated by Henry's reliance on lower-tier advisers and ministeriales, which excluded the magnates from government and threatened their traditional influence. When Henry was excommunicated by Pope Gregory VII in 1076, the princes saw an opportunity to remove him from office.2341

Although Henry's submission to the pope at Canossa temporarily deprived the opposition of canonical arguments for his removal, the princes remained committed to his deposition and sought to replace him with a ruler more aligned with their interests. This conflict triggered a civil war, with Rudolf of Rheinfelden serving as the figurehead for the alliance of papal supporters and disgruntled German princes.14