After finally receiving his regalia, by autumn 1471 he was repudiating the agreement he himself had had a hand in drafting as a chapter member and demanding higher taxes,[7] and to obtain them, he occupied Zons.

With military and financial assistance from his brother Frederick I, Elector Palatine,[8] he began the Cologne Ecclesiastical Conflict (German: Kölner Stiftsfehde), which grew into the Burgundian Wars.

The majority of Ruprecht's vassals, including the citizens of Cologne, renounced their allegiance to him and asked both the Pope and Emperor Frederick III to intervene.

[11] The Siege of Neuss lasted almost a year and ended in Charles accepting the Pope's mediation, including concerning Ruprecht's position as archbishop.

Imprisoned in Burg Blankenstein near Gladenbach and with the Duke of Jülich-Berg acting as mediator, he was forced to renounce his position as archbishop in exchange for an income of 4,000 gold guilders.