or Otto of Brunswick
born 1175/1182
died May 19, 1218, Harzburg Castle, Lower Saxony
German king and Holy Roman emperor.
He was elected German king (1198) by the Guelph faction (see Guelphs and Ghibellines ) but was opposed by the Philip of Swabia. The two factions were at war for several years, but after Philip's murder in 1208 a new election gave the throne to Otto. He was crowned emperor (1209) by Pope Innocent III after agreeing not to claim Sicily. When he violated this pact and conquered southern Italy (1210), the German princes invited Frederick II to replace him. With his uncle, John of England, Otto invaded France, Frederick's ally; defeated at the Battle of {{link=Bouvines, Battle of">Bouvines , he was deposed in 1215.