Princess Dorothea of Saxe-Coburg and Gotha
Princess Dorothea Maria Henriette Auguste Louise of Saxe-Coburg and Gotha (30 April 1881 – 21 January 1967) was a princess of Saxe-Coburg and Gotha  by birth and the duchess of Schleswig-Holstein  through her marriage to Ernst Gunther, duke of Schleswig-Holstein.
Dorothea was born in Vienna, Austria, the second child and only daughter of Prince Philipp of Saxe-Coburg and Gotha and Princess Louise of Belgium.
Prince August Leopold of Saxe-Coburg and Gotha
Prince August Leopold of Saxe- Coburg and Gotha( December 6, 1867 – October 11, 1922), known in Brazil as Dom Augusto Leopoldo, was a prince of the Empire of Brazil and of the House of Saxe- Coburg and Gotha- Koháry.
He was the second of four sons born to German Prince Ludwig August of Saxe- Coburg and Gotha and Princess Leopoldina of Brazil.
The second grandson of the Emperor Pedro II, the prince was, for some years between the presumptive heirs to the Imperial Crown of Brazil.
Their descendants would form the Saxe- Coburg and Gotha branch of the Imperial House of Brazil.
Kelly Rondestvedt
Kelly, Hereditary Princess of Saxe- Coburg and Gotha, Duchess of Saxony( born Kelly Jeanne Rondestvedt on 10 January 1975) is an American investment banker.
Through her marriage to Hubertus, Hereditary Prince of Saxe- Coburg and Gotha, the heir apparent to the defunct ducal throne of Saxe- Coburg and Gotha, she is a princess of the House of Saxe- Coburg and Gotha.
Friedrich Josias, Prince of Saxe-Coburg and Gotha
Friedrich Josias, Prince of Saxe- Coburg and Gotha( Friedrich Josias Carl Eduard Ernst Kyrill Harald; 29 November 1918 – 23 January 1998) was the head of the Ducal Family of Saxe- Coburg and Gotha and titular Duke of Saxe- Coburg and Gotha from 1954 until his death.
Hubertus, Hereditary Prince of Saxe-Coburg and Gotha
Hubertus Michael, Hereditary Prince of Saxe- Coburg and Gotha, Duke of Saxony( born 16 September 1975) is the heir- apparent of the head of the family which ruled the Duchy of Saxe- Coburg and Gotha until 1918.
Princess Teresa Cristina of Saxe-Coburg and Gotha
Princess Teresa Cristina of Saxe- Coburg and Gotha( 23 August 1902 – 24 January 1990), was a German princess of the House of Saxe- Coburg and Gotha.
Ernest II, Duke of Saxe-Coburg and Gotha
Ernest II (German: "Ernst August Karl Johann Leopold Alexander Eduard"; 21 June 181822 August 1893) was the sovereign duke of the Duchy of Saxe-Coburg and Gotha from 29 January 1844 to his death.
He was born in Coburg; his father Ernest III, Duke of Saxe-Coburg-Saalfeld, became Duke Ernest I of Saxe-Coburg and Gotha in 1826 through an exchange of territories.
In 1842, Ernest married Princess Alexandrine of Baden in what was to be a childless marriage.
As reigning Duke, he supported the German Confederation in the Schleswig-Holstein Wars against Denmark, sending thousands of troops and becoming the commander of a German corps; as such, he was instrumental in the 1849 victory at the battle of Eckernförde against Danish forces.
After King Otto of Greece was deposed in 1862, the British government put Ernest's name forward as a possible successor.
Negotiations concerning this failed for various reasons—not least of which was that he would not give up his beloved duchies in favor of the Greek throne.
A supporter of a unified Germany, Ernest watched the various political movements with great interest.
While he initially was a great and outspoken proponent of German liberalism, he surprised many by switching sides and supporting the more conservative (and eventually victorious) Prussians during the Austro-Prussian and Franco-Prussian Wars and subsequent unification of Germany.
His support of the conservatives came at a price however, and he was no longer viewed as the possible leader of a political movement.
According to historian Charlotte Zeepvat, Ernest became "increasingly lost in a whirl of private amusements which earned only contempt from outside".
Ernest and his only full sibling, his younger brother Prince Albert (consort to Queen Victoria of the United Kingdom), were raised as though twins.
They became closer upon the separation and divorce of their parents as well as the eventual death of their mother, Princess Louise of Saxe-Gotha-Altenburg.
Their relationship experienced phases of closeness as well as minor arguments as they grew older.
After Albert's death in 1861, Ernest published anonymous pamphlets against various members of the British royal family.
However, he accepted Albert's second son Prince Alfred, Duke of Edinburgh, as his heir-presumptive.
Upon Ernest's death at Reinhardsbrunn, Alfred succeeded to the ducal throne.
Andreas, Prince of Saxe-Coburg and Gotha
Andreas, Prince of Saxe- Coburg and Gotha, Duke of Saxony( given names:" Andreas Michael Friedrich Hans Armin Siegfried Hubertus"; born 21 March 1943) has been the head of the House of Saxe- Coburg and Gotha since 1998.
He is the grandson of Charles Edward, the last ruling duke of Saxe- Coburg and Gotha.
Alfred, Duke of Saxe-Coburg and Gotha
Alfred( Alfred Ernest Albert; 6 August 184430 July 1900) reigned as Duke of Saxe- Coburg and Gotha from 1893 to 1900.
He was the second son and fourth child of Queen Victoria of the United Kingdom and Prince Albert of Saxe- Coburg and Gotha.
He was known as the Duke of Edinburgh from 1866 until he succeeded his paternal uncle Ernest II as the reigning Duke of Saxe- Coburg and Gotha in the German Empire.
Princess Alexandrine of Baden
Princess Alexandrine of Baden (Alexandrine Luise Amalie Friederike Elisabeth Sophie; 6 December 1820 – 20 December 1904) was the Duchess of Saxe-Coburg and Gotha as the wife of Ernest II.
She was the eldest child of Leopold, Grand Duke of Baden, and his wife Princess Sophie of Sweden.

Question: Who is Ernest Ii, Duke Of Saxe-Coburg And Gotha's mother-in-law?
Answer: Princess Sophie of Sweden