During the War of the Spanish Succession, 1701-14, Louis XIV for the first time in his reign suffered a series of significant military setbacks. An acute crisis was generated in 1708 when the French army was heavily defeated at Oudenarde, leading to the investment and conquest of Vauban’s apparently invincible fortress at Lille in December that provoked panic as the king feared an Allied invasion. Much of the confusion and chaos had been created by Louis XIV, who had placed his inexperienced grandson, the Duc de Bourgogne, in command of the army in Flanders alongside the veteran general, the Duc de Vendôme. Their mutual loathing and heated disagreements hamstrung military operations and the king’s relentless interventions from Versailles seemed to do more harm than good. It compelled his clandestine consort, the Marquise de Maintenon, to become heavily involved in the management of the campaign. This chapter examines these events and her attempts to try and improve the calamitous state of the King’s military affairs against the backdrop of a looming bankruptcy and increasingly vociferous critical public pressure.