Magdalene of Brandenburg (1412–1454)
Magdalene of Brandenburg( born:; died: 27 October 1454 in Scharnebeck) was a princess of Brandenburg by birth and by marriage Duchess of Brunswick- Lüneburg.
Duchess Magdalene Sibylle of Prussia
Magdalene Sibylle of Prussia (31 December 1586 – 12 February 1659) was an Electress of Saxony as the spouse of John George I, Elector of Saxony.
Maurice, Duke of Saxe-Zeitz
Maurice of Saxe-Zeitz (28 March 1619 – 4 December 1681) was a duke of Saxe-Zeitz and member of the House of Wettin.
Born in Dresden, he was the youngest surviving son of John George I, Elector of Saxony, and his second wife Magdalene Sibylle of Prussia.
Magdalena Sibylla of Neidschutz
Magdalena Sibylla of Neidschutz( 8 February 1675 – 14 April 1694), later Countess of Rochlitz, was a German noblewoman and the mistress of John George IV, Elector of Saxony.
She was the first ever Official Mistress(" Favoritin") of an Elector of Saxony.
Magdalena Sibylla, called" Billa", was the daughter of Ursula Margarethe of Haugwitz, who had at one time been the mistress of John George III, Elector of Saxony.
By order of the Elector, Ursula married Colonel Rudolf of Neidschutz, who officially appears as the father of Billa, though there were rumors that Billa was in fact the child of Johann George.
If this had been true, it would have made Billa half- sister of her lover, John George IV.
Billa became mistress of John George IV in late 1691.
By order of his mother, he was forced to marry, in April 1692, in an attempt to break up the affair.
Instead, immediately after he assumed the Electorate, he openly lived with Billa, and she became the first ever Official Mistress(" Favoritin") of an Elector of Saxony.
John George abandoned his wife in the official residence and moved into another palace with Billa.
On 20 February 1693, Leopold I gave her the title" Reichsgräfin von Rochlitz".
She had an illegitimate daughter with John George IV:
John George, Elector of Brandenburg
John George of Brandenburg  (11 September 1525 – 8 January 1598) was a Prince-elector of the Margraviate of Brandenburg (1571–1598) and a Duke of Prussia.
A member of the House of Hohenzollern, he was the son of Joachim II Hector, Elector of Brandenburg, and his first wife Magdalena of Saxony.
Faced with large debts accumulated during the reign of his father, John George instituted a grain tax which drove part of the peasantry into dependence on a nobility that was exempt from taxation.
Though a staunch Lutheran opposed to the rise of Calvinism, he permitted the admission of Calvinist refugees from the wars in the Spanish Netherlands and France.
He was succeeded by his son Joachim Frederick.
Upon the death of his kinsman Albert I, Duke of Prussia in 1568, the Duchy of Prussia was inherited by the latter's underage son Albert Frederick.
John George's father was a co-inheritor of the Duchy of Prussia.
In 1577 the Brandenburg electors became co-regent with Duke Albert Frederick of Prussia.
Francis Erdmann, Duke of Saxe-Lauenburg
Francis Erdmann of Saxe- Lauenburg( Theusing, 25 February 1629 – 30 July 1666, Schwarzenbek), was duke of Saxe- Lauenburg between 1665 and 1666.
He was the eldest son of Duke Julius Henry and his second wife Elisabeth Sophia of Brandenburg, daughter of John George, Elector of Brandenburg.
Magdalene of Brandenburg
Magdalene of Brandenburg, also Magdalene and Magdalen, (7 January 1582 – 4 May 1616) was the daughter of John George, Elector of Brandenburg and his third wife Elisabeth of Anhalt-Zerbst.
She married Louis V, Landgrave of Hesse-Darmstadt.
Elizabeth Charlotte of the Palatinate, Electress of Brandenburg
Elisabeth Charlotte of the Palatinate (19 November 1597 – 26 April 1660) was an Electress consort of Brandenburg as the wife of George William, Elector of Brandenburg and Duke of Prussia, and the mother of Frederick William of Brandenburg, the "Great Elector".
Christian, Margrave of Brandenburg-Bayreuth
Christian, Margrave of Brandenburg- Bayreuth( 30 January 1581 in Cölln – 30 May 1655 in Bayreuth) was a member of the House of Hohenzollern and Margrave of Brandenburg- Kulmbach( later renamed" Brandenburg- Bayreuth").
He was the eldest of eleven children born to John George, Elector of Brandenburg by his third wife Princess Elisabeth of Anhalt- Zerbst.
Magdalena of Saxony
Magdalena of Saxony (7 March 1507 – 25 January 1534) was Margravine of Brandenburg, its "Electoral Princess", the Electoral equivalent of a crown princess.
She was the daughter of George "the Bearded", Duke of Saxony and his wife Barbara.
Magdalena's maternal grandparents were Kazimierz IV Jagiellon and his wife queen Elisabeth of Austria, daughter of Albert II of Germany.
She was a granddaughter of the Elisabeth aforementioned,mother of the Jagiellonians, queen of Poland, who had claimed the Duchy of Luxembourg in 1460s as being the younger daughter of the last Luxembourg heiress Elisabeth of Luxembourg, Queen of Bohemia.
Though by no means an heiress of her grandmother, she was intended to wed
the heir of her grandmother's older sister.
Joachim (1505–1571), the future elector of Brandenburg, was the eldest son and heir of their current claimant of Luxembourg, Joachim I, Elector of Brandenburg (1484–1535), the eldest son and heir of Margaret of Thuringia (1449–1501), Dowager Electress of Brandenburg, herself the eldest daughter and heiress of Anna, Duchess of Luxembourg and William of Saxony, Landgrave of Thuringia.
Magdalena was thus married, at Dresden, on 6 November 1524, to her second cousin's son Joachim Hector, the future Elector of Brandenburg.
Their son was John George, another future Elector of Brandenburg.
After Magdalena's death which occurred well before Joachim ascended the electorate, Joachim II Hector married Hedwig Jagiellon, daughter of King Sigismund I of Poland.

Question: What is the place of birth of John George, Elector Of Brandenburg's mother?