Frederick, Duke of Bavaria
Frederick( 1339 – 4 December 1393) was Duke of Bavaria from 1375.
He was the second son of Stephen II and Elizabeth of Sicily.
Sigismund, Duke of Bavaria
Sigismund of Bavaria (26 July 1439 – 1 February 1501) was a member of the Wittelsbach dynasty.
He ruled as Duke of Bavaria-Munich from 1460 to 1467, and then as Duke of Bavaria-Dachau until his death.
Charles II, Duke of Bourbon
Charles II, Duke of Bourbon( Château de Moulins, 1434 – September 13, 1488, Lyon), was Archbishop of Lyon from an early age and a French diplomat under the rule of Louis XI of France.
He had a 2- week tenure as Duke of Bourbon in 1488, being ousted afterward by his younger brother and successor, Peter II, Duke of Bourbon.
Albert III, Duke of Bavaria
Albert III the Pious of Bavaria- Munich( 27 March 1401 – 29 February 1460), since 1438 Duke of Bavaria- Munich.
He was born in Wolfratshausen to Ernest, Duke of Bavaria and Elisabetta Visconti, daughter of Bernabò Visconti.
Princess Maria Elisabeth of Bavaria
Princess Maria Elisabeth of Bavaria( 9 September 1914 – 13 May 2011) was the eldest daughter of Prince Franz of Bavaria, third son of Ludwig III of Bavaria.
Maria of Brabant, Duchess of Bavaria
Maria of Brabant( 1226–1256) was a daughter of Henry II, Duke of Brabant, and Maria of Swabia.
She married Louis II, Duke of Bavaria, being the first of three wives.
Stephen II, Duke of Bavaria
Stephen II (1319 – 13 May 1375, Landshut) was Duke of Bavaria from 1347 until his death.
He was the second son of Emperor Louis IV the Bavarian by his first wife Beatrice of Silesia and a member of the Wittelsbach dynasty.
Beatrice of Silesia
Beatrice of Silesia (also known as Beatrice of Świdnica; , ; 1290 – 25 August 1320) was a Polish princess member of the House of Piast in the Silesian branch of Jawor-Świdnica and by marriage Duchess of Bavaria and German Queen.
Princess Irmingard of Bavaria
Princess Irmingard of Bavaria( 29 May 1923 – 23 October 2010) was the daughter of Rupprecht, Crown Prince of Bavaria and his second wife, Princess Antonia of Luxembourg.
She was a half- sister of Albrecht, Duke of Bavaria.
John II, Duke of Bavaria
Duke John II of Bavaria- Munich( 1341 – 1397),( German:" Johann II, Herzog von Bayern- München"), since 1375 Duke of Bavaria- Munich.
He was the third son of Stephen II and Elizabeth of Sicily.

Question: What nationality is Stephen Ii, Duke Of Bavaria's mother?
Answer: Polish