Cabbage Patch Emperors

One of the best parts of being a king is that you get an awesome nickname, like the "the Wise", "the Strong" or "the Great" (which usually requires making friends with the guy in charge of picking the nicknames).  Sometimes, though, you get stuck with one of the crappier names, like Louis the Stammerer of France, or Ethelred the Unready of England.

But one monarch in particular showed up way late to nickname assignment day, and really had to scrape the bottom of the barrel:  Emperor Ivaylo the Cabbage of Bulgaria.  In 1277, things were not going well for the Bulgarians.  Mongols were raiding from the North, the Byzantines were eyeing an easy conquest from the South, the economy was in shambles, and the peasants were, of course, getting uppity.  Ivaylo at the time was a lowly swine herder, but he would soon turn out to be perhaps the most uppity peasant of all time.

Ivaylo decided it was time for action, and styled himself as savior of the Bulgarian people, anointed by God to drive out the Mongol invaders.  Given that the crumbling government had driven out exactly zero Mongols, the people were pretty much willing to give anything a try and rallied behind him.  Ivaylo's newly formed peasant army was soon able to push back bands of Mongol raiders.  The Bulgarian Emperor, Constantine I, didn't like a lowly peasant showing him up, so he gathered his army, attacked, and was decisively defeated.  Constantine was killed in battle, leaving his 7-year-old son Michael Asen as the heir to the throne.  Ivaylo, however, married the widowed empress, and had himself crowned emperor.  This was presumably because if you're going to steal a child's crown, you might as well also bone his mother.

Unfortunately, both the Mongols and Byzantines soon grew tired of his antics, and when the full force of the Mongol army was arrayed against him, Ivaylo's mix of serf moxie and swine-herding skills was not enough.  He was driven back to his capital and besieged by the Mongolians.  After three months, he was able to break through the Mongol lines and resumed his string of improbable victories.  He even defeated two armies sent by the Byzantines who presumably didn't want their peasants getting any wise ideas.  In the meantime, though, the nobility of Bulgaria had gathered their forces together, and Ivaylo's army was too beleaguered to fight a third enemy.  He tried seeking refuge with the Mongols, but was assassinated by the khan.  Historians regard this as being a rookie mistake.

Despite his eventual defeat, Ivaylo holds the world record for most successful peasant uprising in European history.  Unlike every other attempt, he actually managed to be recognized as emperor, and led his armies to victories over two of the most powerful nations in history - the Mongol hordes and the Byzantine Empire.  Normally such a feat would earn one of the cool titles like "the Great" or "the Really Great", but the Bulgarians instead named him Ivaylo the Cabbage, because that's way funnier.