At the age of sixteen, he was married to Agnes of the Palatinate, a granddaughter of Duke Henry the Lion and Conrad of Hohenstaufen. With this marriage, the Wittelsbach inherited the Palatinate and kept it as a Wittelsbach possession until 1918. Since that time also the lion has become a heraldic symbol in the coat of arms for Bavaria and the Palatinate.
Otto acquired the rich regions of Bogen in 1240, and Andechs and Ortenburg in 1248 as possessions for the Wittelsbach and extended his power base in Bavaria this way. With the county of Bogen the Wittelsbach acquired also the white and blue coloured lozenge flag which since that time has been the flag of Bavaria (and of the Palatinate).
After a dispute with emperor Frederick II was ended, he joined the Hohenstaufen party in 1241. His daughter, Elizabeth, was married to Frederick's son Conrad IV. Because of this, Otto was excommunicated by the pope.
He died in Landshut in 1253. Like his forefathers, Otto was buried in the crypt of Scheyern Abbey.
Sophie (1236, Landshut – 9 August 1289, Castle Hirschberg), married 1258 to Count Gerhard IV of Sulzbach and Hirschberg.
Agnes (c. 1240–c. 1306), Nun in Segenstal Abbey
Otto had a daughter who died young and whose name is not known. The Annales sancti Rudberti Salisburgenses record her betrothal in 1235 to Conrad, who later married Elisabeth.[2]
Peltzer, Jörg (2013). Die Wittelsbacher und die Kurpfalz im Mittelalter: Eine Erfolgsgeschichte?. Schnell & Steiner. ISBN978-3795426453.
Reiss-Engelhorn-Museen, Mannheim (2013). Die Wittelsbacher am Rhein. Die Kurpfalz und Europa: 2 Bände. Schnell & Steiner. ISBN978-3795426446.
Schmid, Gregor M. (2014). Die Familie, die Bayern erfand: Das Haus Wittelsbach: Geschichten, Traditionen, Schicksale, Skandale. Munich: Stiebner. ISBN978-3830710608.
Vogel, Susanne (2012). Die Wittelsbacher: Herzöge - Kurfürsten - Könige in Bayern von 1180 bis 1918. Biografische Skizzen. Staackmann. ISBN978-3886752485.