Princess Marie Anne of Saxe-Altenburg
Princess Marie Anne of Saxe- Altenburg( 14 March 1864 – 3 May 1918) was the consort of Georg, Prince of Schaumburg- Lippe.
As the eldest daughter of Prince Moritz of Saxe- Altenburg and his wife Princess Augusta of Saxe- Meiningen, and a sister of Ernest II, Duke of Saxe- Altenburg, Marie Anne was a member of the Ducal House of Saxe- Altenburg.
Anna of Saxe-Wittenberg
Anna of Saxe-Wittenberg (died: 18 April 1426) was a member of the House of Ascania and the wife of Duke Frederick I of Brunswick-Lüneburg, a German anti-king.
Anna of Saxe-Wittenberg was the daughter of
Duke Wenceslas I of Saxe-Wittenberg, Duke of Lüneburg and Elector of Saxony and his wife Cecilia of Carrara.
In 1386 she married with Duke Frederick I of Brunswick-Lüneburg.
They had two daughters.
In 1400 Frederick was elected King of the Germans.
This election, however, was not recognized by three of the electors.
Frederick was murdered on the way home, a month after the election.
Anna's second marriage was with Landgrave Balthasar of Thuringia, Margrave of Meissen.
This marriage remained childless.
Princess Charlotte of Saxe-Meiningen
Princess Charlotte of Saxe- Meiningen( 11 September 1751, Frankfurt am Main, Free Imperial City of Frankfurt, Holy Roman Empire – 25 April 1827, Genoa, Kingdom of Sardinia) was a member of the House of Saxe- Meiningen and a Princess of Saxe- Meiningen by birth and a member of the House of Saxe- Gotha- Altenburg and Duchess consort of Saxe- Gotha- Altenburg through her marriage to Ernest II, Duke of Saxe- Gotha- Altenburg.
Albert of Saxe-Wittenberg, Duke of Lüneburg
Albert of Saxe-Wittenberg (died 28 June 1385 in Wittenberg) was born as the son of Otto (d. 30 March 1350), a younger son of the prince-elector Rudolf I of Saxe-Wittenberg, and his (Otto's) wife Elisabeth, daughter of Duke William II of Brunswick-Lüneburg.
In 1370 he succeeded his (maternal) grandfather as the Duke or Prince of Lüneburg.
William II of Brunswick-Lüneburg named his grandson Albert as his heir in Lüneburg because neither he or his brother had male heirs.
In fact William II had previously asked Emperor Charles IV for the eventual enfeoffment of the state to his grandson, but backed away again in the years that followed, because he feared the influence of Albert's uncles, Wenceslas I and Rudolf II.
A further reason may be found in the terms of the Brunswick-Lüneburg investiture agreement of 1235 as well as the succession treaties agreed by William's father Otto the Strict with Brunswick-Lüneburg's Wolfenbüttel line of the House of Welf, according to which the principality had to be passed to any male heir within the entire Welf house if there were one.
After the death of William II and the succession of the Wolfenbüttel Magnus II, the Lüneburg War of Succession broke out between Saxe-Wittenberg and Brunswick-Wolfenbüttel.
Albert was backed by his uncle the Prince-Elector Wenceslas of Saxony (Saxe-Wittenberg).
On 25 July 1373, Duke Magnus was killed in a battle near Leveste on the Deister (part of modern-day Gehrden).
After this an arrangement was agreed between Prince-Elector Wenceslas and Albert, on the one hand and the widow of Magnus II and her sons on the other.
It was agreed that the land would belong, undivided, to the two Ascanians from Saxe-Wittenberg and, after their deaths, would be transferred to the sons of the fallen duke, Magnus II.
And that it should continue to alternate after the deaths of the Welfs, i.e. the succession would pass to the Ascanians again.
In order that this plan could also be reinforced by family ties, in 1374 Albert of Saxe-Lüneburg married the widow of Magnus II, Catharina and chose Celle as his home, which he made a residence in 1378.
The two still underage sons of Magnus also married into the House of Ascania in 1386.
He would rule the Principality of Lüneburg jointly with his uncle Wenceslas until his death on 28 June 1385.
Rudolf III, Duke of Saxe-Wittenberg
Rudolf III( – 11 June 1419), a member of the House of Ascania, was Duke of Saxe- Wittenberg and Elector of Saxony from 1388 until his death.
Rudolf II, Duke of Saxe-Wittenberg
Rudolf II, Duke of Saxe- Wittenberg, nicknamed
Rudolf the Blind,( – 6 December 1370 in Wittenberg) was a member of the House of Ascania, He was Elector of Saxony and Duke of Saxe- Wittenberg from 1356 until his death.
He was the eldest son of Duke Rudolf I of Saxe- Wittenberg and his wife, Judith of Brandenburg- Salzwedel.
Princess Elisabeth Sophie of Saxe-Altenburg
Elisabeth Sophie of Saxe- Altenburg( 10 October 1619 – 20 December 1680), was a princess of Saxe- Altenburg and, by marriage, duchess of Saxe- Gotha.
She was born in Halle, the only daughter of Johann Philipp, Duke of Saxe- Altenburg, and his wife, Elisabeth of Brunswick- Wolfenbüttel.
Wenceslaus I, Duke of Saxe-Wittenberg
Wenceslas I, Duke of Saxe-Wittenberg (– 15 May 1388, in Celle) from the House of Ascania ruled from 1370 to 1388 and was a prince-elector of the Holy Roman Empire as well as Prince of Lüneburg.
He was the son of Rudolf I and his 3rd wife, Agnes of Lindow-Ruppin.
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.
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.

Question: Who is the paternal grandfather of Anna Of Saxe-Wittenberg?
Answer: Rudolf I