Johann Georg was the sixth of eight children and the second son of George of Saxony, the penultimate king of Saxony, and his wife Infanta Maria Ana of Portugal. The prince was raised in Dresden and received a strict Roman Catholic upbringing.
John George I (5 March 1585 – 8 October 1656) was Elector of Saxony from 1611 to 1656. He led Saxony through the Thirty Years' War, which dominated his 45-year reign. Biography Monument to John George in Johanngeorgstadt Born in Dresden, John George was the second son of the Elector Christian I and Sophie of Brandenburg. 
Georg, Crown Prince of Saxony or George (15 January 1893 – 14 May 1943) the last Crown Prince of Saxony, was the heir to the King of Saxony, Frederick Augustus III,  at the time of the monarchy's abolition on 13 November 1918. He later became a Roman Catholic priest and a Jesuit.
Prince Johann Georg Pius Karl Leopold Maria Januarius Anacletus of Saxony, Duke of Saxony (10 July 1869 – 24 November 1938) was the sixth child and second-eldest son of George of Saxony and his wife Infanta Maria Ana of Portugal and a younger brother of the Kingdom of Saxony 's last king, Frederick Augustus III of Saxony. 
Johann George III (20 June 1647 – 12 September 1691) was Elector of Saxony from 1680 to 1691. He belonged to the Albertine line of the House of Wettin . Early life Johann Georg III was born in Dresden, the only son of Johann George II and Magdalene Sybille of Brandenburg-Bayreuth .
– Prince Johann Georg (1869) – Prince Maximilian (1870) – Prince Albert (1875) Reign: June 19, 1902 – October 15, 1904. Died: October 15, 1904, Pillnitz Castle, Dresden Burial Site: New Crypt at the Hofkirche, Dresden. Unofficial Royalty: Georg, King of Saxony; Infanta Maria Ana of Portugal
John of Saxony (24 August 1498 in Dresden – 11 January 1537 in Dresden), also known as "John the Younger" or "Hans of Saxony" was Hereditary Prince of Saxony from the Albertine line of the House of Wettin .
At 12:30 scouts were sent out to inform us of the arrival of the “Indiana” of the Hamb [ur]g.-America line, on which Prince Joh [ann]-Georg of Saxony with wife and sister-in-law, along with Princess Mathilde of Saxony will arrive. [….] Borchardt dashes off to meet them.
Johann (30 June 1468 – 16 August 1532),  known as Johann the Steadfast or Johann the Constant ( Johann, der Beständige ), was Elector of Saxony from 1525 until 1532 from the House of Wettin . He is notable for organising the Lutheran Church in the Electorate of Saxony from a state and administrative level.
Partisan of Johann Georg I of Saxony (reigned 1611–56) German. ca. 1625. On view at The Met Fifth Avenue in Gallery 371. This staff weapon was carried by the bodyguards of the Prince-Electors of Saxony. Public Domain.