Frederick II, Duke of Saxe-Gotha-Altenburg
Frederick II, Duke of Saxe-Gotha-Altenburg (28 July 1676 – 23 March 1732), was a duke of Saxe-Gotha-Altenburg.
He was born in Gotha, the fifth child and first son of Frederick I, Duke of Saxe-Gotha-Altenburg and Magdalena Sibylle of Saxe-Weissenfels.
After the death of his father, in 1691, Frederick II assumed the duchy of Saxe-Gotha-Altenburg.
Because he was still under age, a guardianship and co-regency was formed between his uncles, the dukes
Bernhard I of Saxe-Meiningen and Heinrich of Saxe-Römhild.
In 1693, after he returned from a journey to Holland and England, he wrote to the emperor for a license of adult age and took independent control of the government of his duchy.
Frederick was a splendor-loving baroque ruler; maintaining his court and standing army, which he had taken over from his father and even expanded, devoured a considerable amount of his income.
As a solution, Frederick hired out his soldiers to foreign princes, which caused him great difficulties in 1702, when the King Louis XIV of France hired his troops and used them in his war against the Emperor.
Relating to domestic affairs, Frederick essentially continued the policy of his father.
He created an orphanage in Altenburg (1715), a workhouse and a lunatic asylum in Kahla (1726), as well as the Magdalenenstift - in honor of his mother and wife (both with the same name) - (1705), an endowment for unmarried noble women.
For 100,000 thaler from his private property, he bought the famous numismatic collection of Prince Anton Günther of Schwarzburg Arnstadt, which formed the basis of the current collection of coins ("Münzkabinetts") at Schloss Friedenstein.
By accumulation of parts of Saxe-Coburg (dissolved in 1699), Saxe-Eisenberg (dissolved in 1707) and Saxe-Römhild (dissolved in 1710), he succeeded to all, however only at long hereditary disputes under the other Ernestine duchies, which went only to 1735 with an arbitral award of the Emperor finally to end reaching in each case area increases for his country.
He died in Altenburg.
Anna Sophie of Saxe-Gotha-Altenburg
Duchess Anna Sophie of Saxe- Gotha-Altenburg( 22 December 1670 – 28 December 1728) was a princess of Saxe- Gotha- Altenburg and Duchess in Saxony by birth, and by marriage a Princess of Schwarzburg- Rudolstadt.
Prince John August of Saxe-Gotha-Altenburg
Johann August of Saxe-Gotha-Altenburg (17 February 1704 – 8 May 1767), was a German prince, member of the House of Saxe-Gotha-Altenburg.
He was born in Gotha, the fifth but second surviving son of Frederick II, Duke of Saxe-Gotha-Altenburg and Magdalene Augusta of Anhalt-Zerbst.
Dorothea Maria of Saxe-Gotha-Altenburg
Dorothea Maria of Saxe- Gotha-Altenburg( 12 February 1654 in Gotha – 17 June 1682 in Gotha), was a German princess member of the House of Wettin in the Ernestine branch of Saxe- Gotha- Altenburg.
She was the twelfth child and fourth daughter of Ernest I, Duke of Saxe- Gotha by his wife Elisabeth Sophie, the only daughter of John Philip, Duke of Saxe- Altenburg.
Frederick III, Duke of Saxe-Gotha-Altenburg
Frederick III, Duke of Saxe- Gotha-Altenburg( 14 April 1699 – 10 March 1772), was a duke of Saxe- Gotha- Altenburg.
Ernest II, Duke of Saxe-Gotha-Altenburg
Ernest II, Duke of Saxe-Gotha-Altenburg (Gotha, 30 January 1745 – Gotha, 20 April 1804) was the reigning Duke of Saxe-Gotha-Altenburg from 1772 to 1804.
He was the third but second surviving son of Frederick III, Duke of Saxe-Gotha-Altenburg and Luise Dorothea of Saxe-Meiningen.
The death of his older brother Frederick in 1756 made him the heir to the duchy of Saxe-Gotha-Altenburg.
Fredericka of Saxe-Gotha-Altenburg
Fredericka of Saxe- Gotha-Altenburg( 17 July 1715 – 2 May 1775), was a German noblewoman member of the House of Wettin and by marriage Duchess of Saxe- Weissenfels.
Born in Gotha, she was the fifteenth of nineteen children born from the marriage of Frederick II, Duke of Saxe- Gotha- Altenburg and Magdalena Augusta of Anhalt- Zerbst.
From her eighteen older and younger siblings, only eight survived to adulthood: Frederick III, Duke of Saxe- Gotha- Altenburg, William, John August, Christian William, Louis Ernest, Maurice, Augusta( by marriage Princess of Wales), and John Adolph.
Johann Adolf of Saxe-Gotha-Altenburg
Johann Adolf of Saxe- Gotha-Altenburg( 18 May 1721, Gotha – 29 April 1799, Friedrichstanneck, now a district of Eisenberg, Thuringia), was a German prince of the House of Saxe- Gotha- Altenburg and a Saxon lieutenant general.
Frederick IV, Duke of Saxe-Gotha-Altenburg
Frederick IV, Duke of Saxe-Gotha-Altenburg (Gotha, 28 November 1774 – Gotha, 11 February 1825), was the last duke of Saxe-Gotha-Altenburg.
He was the third but second surviving son of Ernst II, Duke of Saxe-Gotha-Altenburg and Charlotte de Saxe-Meiningen.
After the death of his older brother August without sons (1822), Frederick (the only surviving male of the house) inherited the duchy of Saxe-Gotha-Altenburg.
Frederick fought - after military training - in the Napoleonic campaigns and was heavily wounded.
As a consequence of these injuries, he was constantly ill until his death.
Because of his illness, he traveled for a long time seeking a cure.
During these stays outside of his duchy, he left the government in hands of his secret advisor Bernhard August von Lindenau.
He only reigned three years and died unmarried; with him, the line of Saxe-Gotha-Altenburg ended.
After his death, his lands were repartitioned among his Wettin relations.
Ernst I of Saxe-Coburg-Saalfeld received Gotha, and changed his title to "Duke of Saxe-Coburg and Gotha", although the two duchies remained technically separate in a personal union.
Altenburg was thereafter ruled by the Duke of Saxe-Hildburghausen, whose dukedom was transferred to Saxe-Meiningen along with Saxe-Saalfeld, which Saxe-Coburg gave up in return for receiving Saxe-Gotha.
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.

Question: Who is Prince John August Of Saxe-Gotha-Altenburg's paternal grandmother?