Dorothea Maria of Saxe-Weimar, Duchess of Saxe-Zeitz
Dorothea Maria of Saxe- Weimar( 14 October 1641 – 11 June 1675), was by birth Duchess of Saxe- Weimar from the Ernestine branch of the House of Wettin and by marriage Duchess of Saxe- Zeitz.
Frederick Henry, Duke of Saxe-Zeitz-Pegau-Neustadt
Frederick Heinrich of Saxe-Zeitz-Pegau-Neustadt (b. Moritzburg, 21 July 1668
- d. Neustadt an der Orla, 18 December 1713), was a German prince of the House of Wettin.
He was the fourth (but third surviving) son of Maurice, Duke of Saxe-Zeitz, and his second wife, Dorothea Maria of Saxe-Weimar.
Maurice Wilhelm, Duke of Saxe-Merseburg
Maurice Wilhelm, Duke of Saxe-Merseburg (5 February 1688 – 21 April 1731) was a duke of Saxe-Merseburg and member of the House of Wettin.
He was born in Merseburg, the fifth (but second surviving) son of Christian II, Duke of Saxe-Merseburg, and Erdmuthe Dorothea of Saxe-Zeitz.
Princess Luise Dorothea of Saxe-Meiningen
Luise Dorothea of Saxe- Meiningen( 10 August 1710 – 22 October 1767) was a member of German royalty.
She was born in Meiningen, the daughter of Ernst Ludwig I, Duke of Saxe- Meiningen and Dorothea Marie of Saxe- Gotha.
She was the wife of Frederick III, Duke of Saxe- Gotha- Altenburg.
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.
Anna Fredericka Philippine of Schleswig-Holstein-Sonderburg-Wiesenburg
Anna Fredericka Philippine of Schleswig-Holstein- Sonderburg- Wiesenburg( 4 July 1665- 25 February 1748), was a German noblewoman member of the House of Oldenburg and by marriage Duchess of Saxe- Zeitz- Pegau- Neustadt.
Born in Wiesenburg, she was the thirteenth of fifteen children born from the second marriage of Philip Louis, Duke of Schleswig- Holstein- Sonderburg- Wiesenburg with Anna Margaret of Hesse- Homburg.
From her fourteen full- siblings, only seven survive adulthood: Frederick, Sophie Elisabeth( by marriage Duchess of Saxe- Zeitz), Charles Louis, Eleanor Margaret( by marriage Princess of Liechtenstein), William Christian, Magdalene Sophie( Abbess in Quedlinburg) and Johanna Magdalene Louise.
In addition, she had two further older half- siblings from her father's first marriage with Catharina of Waldeck- Wildungen, of whom only one survive: Dorothea Elisabeth( by her two marriages Countess of Sinzendorf, Rabutin and Marchioness de Fremonville).
Dorothea Marie of Saxe-Gotha-Altenburg
Dorothea Marie of Saxe- Gotha-Altenburg( 22 January 1674 – 18 April 1713) was the wife of Ernst Ludwig I, Duke of Saxe- Meiningen.
She was the daughter of Frederick I, Duke of Saxe- Gotha- Altenburg and his first wife, Magdalena Sybille of Saxe- Weissenfels.
She married Ernst Ludwig I on the 19 September 1704.
Sophie Elisabeth of Schleswig-Holstein-Sonderburg-Wiesenburg
Sophie Elisabeth of Schleswig- Holstein- Sonderburg- Wiesenburg( 4 May 1653- 19 August 1684), was a German noblewoman member of the House of Oldenburg and by marriage Duchess of Saxe- Zeitz.
Born in Homburg vor der Höhe, she was the third of fifteen children born from the second marriage of Philip Louis, Duke of Schleswig- Holstein- Sonderburg- Wiesenburg with Anna Margaret of Hesse- Homburg.
From her fourteen full- siblings, only seven survived adulthood: Frederick, Charles Louis, Eleanor Margaret( by marriage Princess of Liechtenstein), William Christian, Sophie Magdalene( Abbess in Quedlinburg), Anna Fredericka Philippine( by marriage Duchess of Saxe- Zeitz- Pegau- Neustadt) and Johanna Magdalene Louise.
In addition, she had two further older half- siblings from her father's first marriage with Catharina of Waldeck- Wildungen, of whom only one survived: Dorothea Elisabeth( by her two marriages Countess of Sinzendorf, Rabutin and Marchioness de Fremonville).
Christian III Maurice, Duke of Saxe-Merseburg
Christian III Maurice, Duke of Saxe-Merseburg (Merseburg, 7 November 1680 – Merseburg, 14 November 1694), was a duke of Saxe-Merseburg and member of the House of Wettin.
He was the eldest son of Christian II, Duke of Saxe-Merseburg, and Erdmuthe Dorothea of Saxe-Zeitz.
Dorothea Wilhelmine of Saxe-Zeitz
Dorothea Wilhelmine of Saxe- Zeitz( 20 March 1691 – 17 March 1743) was a duchess of Saxe- Zeitz by birth and by marriage Landgravine of Hesse- Kassel.

Question: Who is Frederick Henry, Duke Of Saxe-Zeitz-Pegau-Neustadt's paternal grandfather?
Answer: John George I, Elector of Saxony