Archduchess Maria Anna of Austria (1835–1840)
Archduchess
Maria Anna of Austria( 27 October 1835 – 5 February 1840), was by birth an Archduchess of Austria and member of the House of Habsburg.
She was the fourth child and only daughter of Archduke Franz Karl of Austria and his wife, Princess Sophie of Bavaria, daughter of Maximilian I Joseph of Bavaria and his second wife Caroline of Baden.
Princess Auguste of Bavaria (1875–1964)
Princess Auguste of Bavaria( 28 April 1877 – 25 June 1964) was a member of the Bavarian Royal House of Wittelsbach and the spouse of Archduke Joseph August of Austria.
Archduke Joseph Karl of Austria
Archduke Joseph Karl of Austria (2 March 1833 in Pressburg – 13 June 1905 in Fiume) was a member of the Habsburg dynasty.
He was the second son of Archduke Joseph, Palatine of Hungary (7th son of Leopold II, Holy Roman Emperor) and Duchess Maria Dorothea of Württemberg.
Like many junior members of royal families, Archduke Joseph Karl entered the military.
He became a Major General in the Austrian Army in 1860.
During the Austro-Prussian War he commanded a Brigade in the North Army and had three horses shot under him at Königgrätz.
In 1867, he became Palatine of Hungary after the death of his childless half-brother Stephen, though the post by that time was symbolic only.
The archduke had an interest in Romani language and occasionally wrote on this topic to Albert Thomas Sinclair, an American lawyer who shared this interest.
A biography of Sinclair notes that the archduke sent a copy of his work, “a large octavo volume handsomely bound It is a most important and valuable philological work comparing the gypsy words with Sanskrit, Hindustani Persian, etc.”
Archduke Joseph August of Austria
Archduke Joseph August Viktor Klemens Maria of Austria, Prince of Hungary and Bohemia( 9 August 1872 – 6 July 1962) was a" Feldmarschall"( Field Marshal) of the Austro- Hungarian Army and for a short period head of state of Hungary.
He was a member of the House of Habsburg- Lorraine, the eldest son of Archduke Joseph Karl of Austria( 1833 – 1905) and his wife Princess Clotilde of Saxe- Coburg and Gotha( 1846–1927).
Joseph August's grandfather had been Palatine Joseph of Hungary( 1776 – 1847), Palatine and Viceroy of Hungary, a younger son of Emperor Leopold II.
The Archduke Joseph Diamond, a 76.02 carat colourless diamond with internal flawless clarity, is named after the Archduke and officially recorded as his property.
Duchess Maria Dorothea of Württemberg
Duchess Maria Dorothea of Württemberg (Maria Dorothea Luise Wilhelmine Caroline; 1 November 1797 in Carlsruhe (now Pokój), Silesia – 30 March 1855 in Pest, Hungary) was the daughter of Duke Louis of Württemberg (1756–1817) and Princess Henriette of Nassau-Weilburg (1780–1857).
Archduke Joseph Árpád of Austria
Archduke Joseph Árpád Benedikt Ferdinand Franz Maria Gabriel (8 February 1932 – 30 April 2017) was a member of the Hungarian Palatine branch of the House of Habsburg-Lorraine.
He was born in Budapest, the son of Archduke Joseph Francis of Austria and his wife, Princess Anna of Saxony.
He was the great-grandson of Archduchess Gisela of Austria.
He received a degree in economics from the University of Lisbon.
Archduke Franz Karl of Austria
Archduke Franz Karl Joseph of Austria (17 December 1802 – 8 March 1878) was a member of the House of Habsburg-Lorraine.
He was the father of two emperors:
Franz Joseph I of Austria and Maximilian I of Mexico.
Through his third son Karl Ludwig, he was the grandfather of Archduke Franz Ferdinand of Austria – whose assassination sparked the hostilities that led to the outbreak of World War I – and the great-grandfather of the last Habsburg emperor Karl I.
Eduard von Habsburg
Eduard von Habsburg( born January 12, 1967), also known as Archduke Eduard of Austria is Hungary ’s ambassador to the Holy See and Sovereign Military Order of Malta.
He is son of Archduke Michael of Austria( Archduke Joseph Francis's youngest child) and the great- great- grandson of Emperor Franz Joseph I.
He is married to Baroness Maria Theresia von Gudenus, descendant of Archduke Johann of Austria and has six children.
Archduke Otto of Austria (1865–1906)
Archduke Otto Franz Joseph Karl Ludwig Maria of Austria (21 April 1865 – 1 November 1906) was the second son of Archduke Karl Ludwig of Austria (younger brother of Emperor Franz Joseph I of Austria) and his second wife, Princess Maria Annunciata of Bourbon-Two Sicilies.
He was the father of Charles I of Austria, the last Emperor of Austria.
Princess Clotilde of Saxe-Coburg and Gotha
Princess Marie Adelheid Amalie" Clotilde" of Saxe- Coburg and Gotha, full German name:" Marie Adelheid Amalie Clotilde, Prinzessin von Sachsen- Coburg und Gotha, Herzogin zu Sachsen"( 8 July 1846, Neuilly- sur- Seine, Île- de- France, Kingdom of the French – 3 June 1927, Alcsút, Hungary) was a Princess of Saxe- Coburg and Gotha by birth and an Archduchess of Austria through her marriage to Archduke Joseph Karl of Austria.

Question: Who is Archduke Joseph Karl Of Austria's maternal grandfather?
Answer: Duke Louis of Württemberg