== Prelude ==
Under Charles's father, [[Philip the Good]], the Duchy of Burgundy had allied itself to the cause of the newly elected [[Electorate of Cologne|Archbishop of Cologne]], [[Ruprecht of the Palatinate (Archbishop of Cologne)|Ruprecht]]. Ruprecht proved immensely unpopular, and by 1471 several major towns in the archbishopric, as well as the Kölners themselves, were on the verge of revolt. Attempts by the Emperor [[Frederick III]] to mediate the conflict failed, and in 1474 Charles the Bold signed a treaty with Ruprecht which stipulated that Charles would subdue the rebels and serve as Ruprecht's lifelong protector in return for 200,000 florins a year. To secure his western border, Charles concluded a treaty with [[Louis XI of France]] and then prepared to march into the Rhine valley; contemporaries suspected his real motive was the eventual reconquest of all of [[Alsace]].
== The Siege ==