A war with France called him back, in the course of which he suffered a severe defeat at Bethune.

At the beginning of 1488 Ghent and Bruges once more rebelled; and the Roman king, enticed to enter Bruges, was there seized and compelled to see his friends executed in the market-place beneath his prison window.

For seven months he was held a prisoner; nor was he released until he had sworn to surrender his powers, as regent, to a council of Flemings and to withdraw all his foreign troops from the Netherlands.

He was forced to give hostages as a pledge of his good faith, among them his general, Philip of Cleef, who presently joined his captors.
Maximilian, on arriving at the camp of the Emperor Frederick III, who had gathered together an army to release his imprisoned son, was persuaded to break an oath given under duress.

He advanced therefore at the head of his German mercenaries into Flanders, but was able to achieve little success against the Flemings, who found in Philip of Cleef an able commander.