It was arranged that Charles' only daughter and heiress should be betrothed to Maximilian of Austria, the emperor's eldest son, and the very day and hour for the coronation were fixed.

But the Burgundian had an enemy in Louis XI of France, who was as prudent and far-seeing as his rival was rash and impetuous, and who was far more than his match in political craft and cunning.

French secret agents stirred up Frederick's suspicions against Charles' designs, and the emperor suddenly left Trier, where he had felt humiliated by the splendour of his powerful vassal.
The duke was furious at his disappointment, but was only the more obstinately bent on carrying out his plans.

But Louis had been meanwhile forming a strong league (League of Constance, March 1474) of various states threatened by Charles' ambitious projects.

Duke Sigismund of Austria, Baden, Basel, Elsass, and the Swiss Cantons united under the leadership of France to resist them.