BreezeCauthon

At one point during the Hundred Years' War (actually a series of conflicts lasting 114 years) between France and England, the two sides became involved in a proxy war for the throne of Castile (a powerful kingdom in modern Spain).

England backed King Pedro (known, presumably depending on one's allegiances, as either Pedro the Cruel or Pedro the Just), while France supported another claimant, Pedro's half-brother Henry of Trastamara. 

But there was a third country involved in this proxy war - Navarre, a neighboring Spanish kingdom, led by the ignominiously named Charles the Bad. Navarre was officially an ally of Pedro, but Charles, being the Bad boy that he was, didn't stick to his word. In 1365, he secretly agreed to allow French forces through Navarre to attack Castile and elevate Henry to the throne.

But Charles, being Bad, didn't intend to follow this agreement either. Probably thinking he was terribly clever, he attempted to close the Castile-Navarre border to the British troops, refusing to aid either side. Unfortunately for Charles, the French weren't fazed by this and simply marched into Castile anyway. Charles ended up just paying them a bunch of money to not plunder too much.

Eventually, Pedro was deposed and fled to English-controlled Aquitaine, a region in France. The English launched a campaign to reinstate him. As a part of this, Charles agreed to open the Navarrese borders into Castile and support the English/Pedro-ish cause in exchange for money and territory.

In a boldly original move for Charles, he then went to Castile and agreed, in exchange for money and territory, to close the borders and support Henry's cause.

The English didn't think much of this, and prepared to invade Navarre. Charles rushed back to them and agreed to open the borders after all. Then, having made promises to both sides and not wishing to keep either of them, he hired a French knight to 'kidnap' him and 'hold him hostage' until the fighting in Castile was over. Apparently, Charles and his accomplices were pretty Bad actors, because everybody saw through the ruse and making fun of Charles became a popular source of entertainment in Western Europe.

Charles' death, incidentally, was a strange one. The exact story varies, but everyone agrees that for whatever reason, his doctor prescribed for him to be wrapped tightly in a linen sack doused in alcohol, which by some freak accident caught on fire and... well, that was that for Charles. The end.