Infanta Blanca of Spain
Infanta Blanca of Spain (7 September 1868 – 25 October 1949) was the eldest child of Carlos, Duke of Madrid, Carlist claimant to the throne of Spain and his wife Princess Margherita of Bourbon-Parma.
Blanca was a member of the House of Bourbon and - according to the Carlists - an Infanta of Spain by birth.
In 1889 she married Archduke Leopold Salvator of Austria.
The couple had ten children.
The family left Austria after the end of the Monarchy and finally settled in Barcelona.
When the male line of Blanca's family died out at the death of her uncle, Alfonso Carlos, Duke of San Jaime, some of the Carlists recognized her as the legitimate heiress to the Spanish throne.
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.
Archduke Anton of Austria
Archduke Anton of Austria (Anton Maria Franz Leopold Blanka Karl Joseph Ignaz Raphael Michael Margareta Nicetas von Habsburg-Lorraine; Vienna, 20 March 1901 – Salzburg, 22 October 1987) was an Archduke of Austria and Prince of Tuscany.
He was the seventh of ten children born to Archduke Leopold Salvator of Austria, Prince of Tuscany, and Infanta Blanca of Spain, daughter of Carlos, Duke of Madrid.
Archduke Franz Josef of Austria, Prince of Tuscany
Archduke Franz Josef of Austria- Tuscany (born in Vienna 4 February 1905 - died Hernstein, Austria 9 May 1975) was the fourth son of Archduke Leopold Salvator, Prince of Tuscany and Infanta Blanca of Spain.
At the fall of Habsburg monarchy he moved to Barcelona, where he became a naturalized Spanish citizen.
He married morganatically twice and had a daughter from his second marriage.
During World War II he lived in the United States, working in the forestry industry.
In 1955 he returned to Austria.
He inherited the Carlist pretensions to the Spanish throne of his brother Archduke Karl Pius and called himself Duke of Madrid.
He died in 1975.
Archduke Stefan of Austria
Archduke Stefan of Austria, Prince of Tuscany( 15 August 1932 in Mödling, Lower Austria, Austria – 12 November 1998 in Brighton, Michigan, United States) was a member of the House of Habsburg an Archduke and Prince of Tuscany by birth.
Stefan was the eldest child and son of Archduke Anton of Austria and his wife Princess Ileana of Romania.
Archduchess Elisabeth Amalie of Austria
Archduchess Elisabeth Amalie of Austria (7 July 1878 – 13 March 1960) was a daughter of Archduke Karl Ludwig of Austria and his third wife Infanta Maria Theresa of Portugal.
She was the mother of Franz Joseph II, Prince of Liechtenstein, and the paternal grandmother of Hans-Adam II, Prince of Liechtenstein.
Archduke Hubert Salvator of Austria
Archduke Hubert Salvator of Austria, Prince of Tuscany( 30 April 1894 in Schloss Lichtenegg, Wels, Upper Austria, Austria –Hungary – 24 March 1971 in Schloss Persenbeug, Persenbeug- Gottsdorf, Lower Austria, Austria) was a member of the Tuscan line of the House of Habsburg and Archduke of Austria, Prince of Tuscany by birth.
Archduke Karl Ludwig of Austria
Archduke Karl Ludwig Joseph Maria of Austria( 30 July
1833 – 19 May 1896) was the younger brother of Franz Joseph I of Austria( 1830 – 1916), the father of Archduke Franz Ferdinand of Austria( 1863 – 1914), whose assassination ignited World War I, and grandfather of the last emperor, Charles I.
Archduke Karl Pius of Austria, Prince of Tuscany
Archduke Karl Pius of Austria, Prince Royal of Hungary and Bohemia, Prince of Tuscany (4 December 1909 – 24 December 1953), called "Carlos Pío de Habsburgo-Lorena y de Borbón" in Spain, was a member of the Tuscan branch of the Imperial House of Habsburg and a Carlist claimant to the throne of Spain under the assumed name of "Carlos VIII".
He was the tenth and youngest child of Archduke Leopold Salvator, Prince of Tuscany and Infanta Blanca of Spain.
Archduke Rainer of Austria (1895–1930)
Archduke Rainer of Austria;( 21 November 1895 – 25 May 1930) was a member of the House of Habsburg- Lorraine, a member of the Tuscan branch of the Imperial House of Habsburg, an Archduke of Austria and Prince of Tuscany by birth.
He was the eldest son Archduke Leopold Salvator of Austria, Prince of Tuscany.
He served as officer in the Austrian army during World War I.
At the fall of the Habsburg dynasty, he remained in Vienna and worked for a time as taxi driver.
He died unmarried at the age of 34 from blood- poisoning.

Question: Who is the maternal grandfather of Archduke Karl Pius Of Austria, Prince Of Tuscany?
Answer: Carlos, Duke of Madrid