Otto was born in
Burghausen, the son of
Henry XIII, Duke of Bavaria, and
Elizabeth of Hungary. He succeeded his father in 1290 as duke of Lower Bavaria, together with his younger brothers,
Louis III and
Stephen I. Otto was in opposition to
Habsburg and tried to regain
Styria which Bavaria had lost in 1180. He supported
Adolf, King of Germany against Habsburg and fought on his side in the
Battle of Göllheim. The Hungarian crown was offered to Otto, a grandson of
Béla IV of Hungary, in 1301 but he did not accept before 1305. In August 1305, his opponent,
Wenceslaus III of Bohemia, who had inherited Bohemia from his father, renounced his claim to Hungary on behalf of Otto III. Since the Habsburg
Albert I of Germany was blocking the way through Austria, Otto disguised himself as a merchant, and reached
Buda in November 1305. Otto was then crowned with the
Holy Crown of Hungary in
Székesfehérvár by
Benedict Rád,
Bishop of Veszprém and
Anthony, Bishop of Csanád on 6 December 1305. However, he was not able to strengthen his rule. In the course of 1306, Otto's second opponent
Charles of Anjou occupied
Esztergom,
Szepes Castle,
Zólyom and some other fortresses in the northern parts of the kingdom, and in the next year he also occupied Buda. In June 1307, Duke Otto III visited the powerful
Voivode of Transylvania,
Ladislaus Kán, but the latter imprisoned him. On 10 October 1307, the magnates presented at the
assembly in Rákos proclaimed Charles king, but the most powerful aristocrats (
Matthew III Csák,
Amadé Aba and Ladislaus Kán) ignored him as well. At the end of the year, Ladislaus Kán set Otto free who then left the country, but the Voivode of Transylvania still denied to hand over the Holy Crown of Hungary to Charles, whose legitimacy could be questioned without the coronation with the Holy Crown. Otto abdicated the Hungarian throne in 1308. Otto's involvement in Austrian and Hungarian affairs weakened his position in Bavaria and finally led to failure due to financial problems. In Hungarian historiography he is noted as an
anti-king during the
interregnum of 1301–1310. During his presence in Hungary 1305–1308 Lower Bavaria was ruled by his brother Stephen I. In 1310 a new war against Habsburg devastated
Burghausen. Otto died in 1312 and was succeeded in Lower Bavaria by his son
Henry XV, who shared power with his cousins,
Henry XIV and
Otto IV, both sons of Stephen I.
John I, a son of Henry XIV, was the last duke of Lower Bavaria before
Louis IV, Holy Roman Emperor inherited the country and reunited the duchy in 1340. ==Marriages and children==