“To-day, November 3, 1473, Messire Olivier de la Marche ... took
    the oath of office of master and overseer of the land and duchy of
    Guelders."[5]

The charge of the ducal children, Charles and Philippa, was entrusted to the duke who, in his turn, deputed Margaret of York to supervise their education.  In a comparatively brief time agitation in behalf of the disinherited heir ceased, and imperial ratification alone was required to stamp the territory as a legal fraction of the Burgundian domains.  Under the circumstances the minor heirs were the emperor’s wards, and it was his express duty to look to their interests, but Frederic III. showed no disposition to assert himself as their champion.  On the contrary, the embassy that arrived from his court on August 14th was charged with felicitations to his dear friend, Charles of Burgundy, for his acquisition, and with assurances that the requisite investiture into his dignities should be given by his imperial hand at the duke’s pleasure.[6]

Communication between Frederic and Charles had been intermittently frequent during the past three years, and one subject of their letters was probably a reason why Charles had been willing to abandon a losing game in France to give another bias to his thoughts.  He was lured on by the bait of certain prospects, varying in their definite form indeed, but full of promise that he might be enabled, eventually, to confer with Louis XI. from a better vantage ground than his position as first peer of France.  The story of these hopes now becomes the story of Charles of Burgundy.

When Sigismund of Austria completed his mortgage, in 1469, at St. Omer, and returned home, as already stated, he was fired with zeal to divert some of the dazzling Burgundian wealth into the empty imperial coffers.  An alliance between Mary of Burgundy and the young Archduke Maximilian seemed to him the most advantageous matrimonial bargain possible for the emperor’s heir.  He urged it upon his cousin with all the eloquence he possessed, and was lavish in his offers to be mediator between him and his new friend Charles.

Frederic was impressed by Sigismund’s enthusiastic exposition of the advantages of the match, and little time elapsed before his ambassador brought formal proposals to Charles for the alliance.  The duke received the advances complacently and returned propositions significant of his personal ambitions.  As early as May, 1470, his instructions to certain envoys sent to the intermediary, Sigismund, are plain.  In unequivocal terms, his daughter’s hand is made contingent on his own election as King of the Romans, that shadowy royalty which veiled the approach to the imperial throne.