Johann Georg, Duke of Saxe-Weissenfels
Johann Georg, Duke of Saxe- Weissenfels( 13 July 1677, in Halle – 16 March 1712, in Weissenfels), was a duke of Saxe- Weissenfels- Querfurt and a member of the House of Wettin.
He was the third child and first surviving son of Johann Adolf I, Duke of Saxe- Weissenfels, by his first wife, Johanna Magdalena of Saxe- Altenburg.
Georg Albrecht of Saxe-Weissenfels, Count of Barby
Georg Albrecht of Saxe-Weissenfels, Count of Barby (b. Dessau, 19 April 1695 – d. Barby, 12 June 1739), was a German prince of the House of Wettin and the last count of Barby.
He was the sixth (but second surviving) son of Heinrich of Saxe-Weissenfels, Count of Barby, and Elisabeth Albertine of Anhalt-Dessau.
Albrecht of Saxe-Weissenfels
Albrecht of Saxe- Weissenfels( 14 April 1659 in Halle – 9 May 1692 in Leipzig), was a German prince of the House of Wettin.
He was the fifth and youngest son of August, Duke of Saxe- Weissenfels, and his first wife, Anna Maria of Mecklenburg- Schwerin.
Johanna Magdalene of Saxe-Weissenfels
Johanna Magdalene of Saxe- Weissenfels( 17 March 1708 – 25 January 1760), was a Duchess consort of Courland.
She married the Duke of Courland, Ferdinand Kettler, on 20 September 1730.
She was the daughter of Johann Georg, Duke of Saxe- Weissenfels and Fredericka Elisabeth of Saxe- Eisenach.
The marriage was childless.
Christian, Duke of Saxe-Weissenfels
Christian, Duke of Saxe- Weissenfels( 23 February 1682 in Weissenfels – 28 June 1736 in Sangerhausen), was a duke of Saxe- Weissenfels- Querfurt and member of the House of Wettin.
He was the sixth( but second surviving) son of Johann Adolf I, Duke of Saxe- Weissenfels, and Johanna Magdalena of Saxe- Altenburg.
Princess Elisabeth Albertine of Anhalt-Dessau
Elisabeth Albertine of Anhalt-Dessau (1 May 1665 - 5 October 1706), was a German noblewoman by birth Princess of Anhalt-Dessau as member of the House of Ascania and by marriage Duchess of Saxe-Weissenfels-Barby.
Born in Cölln an der Spree, she was the fourth of ten children born from the marriage of John George II, Prince of Anhalt-Dessau and Henriette Catherine of Orange-Nassau.
From her nine older and younger siblings, five survive adulthood: Henriette Amalie (by marriage Princess of Nassau-Dietz), Marie Eleonore (by marriage Princess Radziwiłł and Duchess of Olyka), Henriette Agnes, Leopold I, Prince of Anhalt-Dessau and Johanna Charlotte (by marriage Margravine of Brandenburg-Schwedt).
Magdalena Sibylla of Saxe-Weissenfels (1673–1726)
Magdalene Sibylle of Saxe- Weissenfels
( 3 September 1673 – 28 November 1726), was a German noblewoman member of the House of Wettin( Albertine line) and by marriage Duchess of Saxe- Eisenach.
Born in Halle, she was the oldest daughter and first child of Duke Johann Adolf I of Saxe- Weissenfels and his wife Johanna Magdalena, the daughter of Duke Frederick William II of Saxe- Altenburg.
She was named after her paternal great- grandmother, Duchess Magdalene Sibylle of Prussia.
Johann Adolf II, Duke of Saxe-Weissenfels
Johann Adolf II, Duke of Saxe- Weissenfels
( Weissenfels, 4 September 1685 – Leipzig, 16 May 1746), was the last duke of Saxe- Weissenfels- Querfurt and a member of the House of Wettin.
He was also a commander in the Saxon army.
Johann Adolf was the youngest of the eleven children of Johann Adolf I, Duke of Saxe- Weissenfels, and Johanna Magdalena of Saxe- Altenburg.
His mother died five months after his birth, on 22 January 1686.
Frederick, Duke of Saxe-Weissenfels-Dahme
Frederick of Saxe- Weissenfels(" Frederick Erdmann"; b. Halle, 20 November
1673- d. Dahme, 16 April 1715), was a German prince member of the House of Wettin and Duke of Saxe- Weissenfels- Dahme.
He was the sixth son of Augustus, Duke of Saxe- Weissenfels but first- born from his second marriage with Johanna Walpurgis of Leiningen- Westerburg.
Johann Adolf I, Duke of Saxe-Weissenfels
Johann Adolf I, Duke of Saxe- Weissenfels( 2 November 1649, in Halle – 24 May 1697, in Weissenfels), was a duke of Saxe- Weissenfels- Querfurt and member of the House of Wettin.
He was the first son of Augustus, Duke of Saxe- Weissenfels, and his first wife, Anna Maria of Mecklenburg- Schwerin.

Question: Who is the maternal grandfather of Georg Albrecht Of Saxe-Weissenfels, Count Of Barby?
Answer: John George II