From 1375 to 1392, Stephen ruled Bavaria with his brothers
Frederick and
John II. However, in 1392, Bavaria was split into three separate Duchies, now consisting of
Bavaria-Landshut,
Bavaria-Ingolstadt and
Bavaria-Munich. John II partitioned Bavaria as the result of his refusal to finance his brothers' expensive ambitions in the Italian court. After the division of Bavaria, Stephen retained Bavaria-
Ingolstadt, although he soon came to regard his share to be inferior to the other two Duchies. From 1395 to 1397, he also jointly held Bavaria-Munich with John II, after an armed conflict between the brothers.
After the deaths of both of his brothers, Stephen attempted to extend his Duchy, this time causing conflict with his nephews. In opposition to them, Stephen also supported King
Rupert against the
Luxemburg. In 1402 Stephen was forced by his nephew
Ernest to confine his reign to Bavaria-
Ingolstadt. In 1403, he supported the citizens' uprising in Munich, although that failed. His final attempt in 1410 to reconquer
Tyrol, which his father had ceded to the Grand Duchy of
Habsburg was likewise unsuccessful.
Adams, Tracy (2010). The Life and Afterlife of Isabeau of Bavaria. The Johns Hopkins University Press.
Pitti, Bonaccorso (2015). "Memoirs". In Branca, Vittore (ed.). Merchant Writers: Florentine Memoirs from the Middle Ages and Renaissance. University of Toronto Press. pp. 254–343.