king charles XII
King of Sweden in the early 1700s', was crowned King when he was a teenager. Denmark, Poland, and Russia then all declared war on Sweden. Despite the triple alliance thinking they'd have an easy time of conquering Sweden, turned out little Charles was a military genius and opened a can of whoop-ass on Denmark and Poland, and was defeated in Ukraine by the Russians in winter. He died when he looked out of a trench and got shot in the head by a sniper.
King Charles XII personally held the gates of Krakow open so that his entire army could flood the city.