The King of France, who had hoped to obtain the hand of Mary for his son the dauphin, caused the suspicion to be whispered into the ear of Frederic that the Duke of Burgundy sought the kingly crown only as the first step to the imperial crown; and that so soon as the dukedom was elevated into a kingdom, Charles, the Duke of Burgundy, would avail himself of his increased power, to dethrone Frederic and grasp the crown of Germany.

This was probably all true.
Charles, fully understanding the perfidious nature of Frederic, did not dare to solemnize the marriage until he first should be crowned.
Frederic, on the other hand, did not dare to crown the duke until the marriage was solemnized, for he had no confidence that the duke, after having attained the regal dignity, would fulfill his pledge.
Charles was for hurrying the coronation, Frederic for pushing the marriage.

A magnificent throne was erected in the cathedral at Treves, and preparations were making on the grandest scale for the coronation solemnities, when Frederic, who did not like to tell the duke plumply to his face that he was fearful of being cheated, extricated himself from his embarrassment by feigning important business which called him suddenly to Cologne.

A scene of petty and disgraceful intrigues ensued between the exasperated duke and emperor, and there were the marching and the countermarching of hostile bands and the usual miseries of war, until the death of Duke Charles at the battle of Nancy on the 5th of January, 1477.
The King of France now made a desperate endeavor to obtain the hand of Mary for his son.

One of the novel acts of this imperial courtship, was to send an army into Burgundy, which wrested a large portion of Mary's dominions from her, which the king, Louis XI., refused to surrender unless Mary would marry his son.