Charles XIV John of Sweden

Born in Pau in 1763, Jean-Baptiste Bernadotte joined the French Royal Army at seventeen and rose through Revolutionary fervor to brigadier general by 1794. His turbulent relationship with Napoleon didn't prevent a marshal's baton or the title Prince of Pontecorvo after Austerlitz. Then in 1810 came the strangest turn: a Swedish courtier campaigned to make this French general heir to childless Charles XIII, and the Riksdag agreed. Renamed Charles John, he became regent and de facto ruler almost immediately. When Napoleon invaded Swedish Pomerania in 1812, the former marshal engineered the Sixth Coalition, co-wrote the Trachenberg Plan, and commanded the army that shattered French forces at Leipzig. He invaded Denmark to secure Norway for Sweden under the Treaty of Kiel, then crushed Norwegian resistance in nineteen days - Sweden's last war. He ascended the throne in 1818 and reigned twenty-six years, the first Bernadotte in a line unbroken to this day.