Prince Philip of Bourbon-Two Sicilies
Prince Philip of Bourbon- Two Sicilies( Filippo Maria Alfonso Antonio Ferdinando Francesco di Paola Lodovico Enrico Alberto Taddeo Francesco Saverio Uberto; 10 December 1885 – 9 March 1949) was a member of the House of Bourbon- Two Sicilies and a Prince of Bourbon- Two Sicilies.
Princess Urraca of Bourbon-Two Sicilies
Princess Urraca of Bourbon- Two Sicilies( July 14, 1913, Nymphenburg Palace, Munich, Kingdom of Bavaria – May 3, 1999, Sigmaringen, Baden- Württemberg, Germany) was a member of the House of Bourbon- Two Sicilies and a Princess of Bourbon- Two Sicilies.
Leopold, Prince of Salerno
Leopoldo Giovanni Giuseppe Michele of Bourbon- Two Sicilies, Prince of Salerno( 2 July 1790, Naples, Kingdom of Naples – 10 March 1851, Naples, Kingdom of the Two Sicilies) was a member of the House of Bourbon- Two Sicilies and a Prince of Bourbon- Two Sicilies.
Prince Carlo, Duke of Castro
Prince Carlo of Bourbon- Two Sicilies, Duke of Castro( born 24 February 1963) is a claimant to the headship of the House of Bourbon- Two Sicilies.
Maria Carolina Zamoyska
Princess Maria Carolina of Bourbon- Two Sicilies, Duchess of Castro( née Countess Maria Carolina Zamoyska)( 22 September 1896 in Kraków, Austria- Hungary – 9 May 1968 in Marseille, France) was the wife of Prince Ranieri, Duke of Castro, claimant to the headship of the House of Bourbon- Two Sicilies.
Carolina was the sixth child and youngest daughter of Polish nobleman Andrzej Przemysław Zamoyski, Count Zamoyski and his wife Princess Maria Carolina of Bourbon- Two Sicilies.
Carolina's maternal grandparents were Prince Francis of Bourbon- Two Sicilies, Count of Trapani and his wife Archduchess Maria Isabella of Austria, Princess of Tuscany.
Duchess Elisabeth of Württemberg (b. 1933)
Duchess Elisabeth of Württemberg( born 2 February 1933) is a member of the House of Württemberg and a Duchess of Württemberg by birth and through her marriage to Prince Antoine of Bourbon- Two Sicilies, a member of the House of Bourbon- Two Sicilies and a Princess of Bourbon- Two Sicilies.
Prince Louis, Count of Aquila
Prince "Luigi" Carlo Maria Giuseppe of Bourbon-Two Sicilies, Count of Aquila (19 July 1824 – 5 March 1897) was a member of the House of Bourbon-Two Sicilies.
Princess Maria Immaculata of Bourbon-Two Sicilies (1874–1947)
Princess" Maria Immaculata" Cristina Pia Isabella of Bourbon- Two Sicilies( Full Italian name:" Maria Immacolata Speranza Pia Teresa Cristina Filomena Lucia Anna Isabella Cecilia Apollonia Barbara Agnese Zenobia, Principessa di Borbone delle Due Sicilie")( 30 October 1874 – 28 November 1947) was the fourth child and eldest daughter of Prince Alfonso of Bourbon- Two Sicilies, Count of Caserta and his wife Princess Maria Antonietta of Bourbon- Two Sicilies.
Duchess Mathilde Ludovika in Bavaria
Mathilde Ludovika, Duchess in Bavaria (30 September 1843 – 18 June 1925) was the fourth daughter of Maximilian, Duke in Bavaria and Princess Ludovika of Bavaria.
Her mother was the youngest daughter of King Maximilian
I Joseph of Bavaria by his second wife Margravine Karoline of Baden.
Princess Maria Teresa of Bourbon-Two Sicilies (1867–1909)
Princess "Maria Teresa" Maddalena of Bourbon-Two Sicilies (Full Italian name: "Principessa Maria Teresa Maddalena di Borbone delle
Due Sicilie")
(15 January 1867, Zürich, Switzerland – 1 March 1909, Cannes, France) was the only child of Prince Louis of Bourbon-Two Sicilies, Count of Trani (heir apparent of the defunct throne of the Two Sicilies) and his wife Duchess Mathilde Ludovika in Bavaria.
Maria Teresa was a member of the House of Bourbon-Two Sicilies and became a member of the House of Hohenzollern-Sigmaringen and titular Princess of Hohenzollern through her marriage to Prince Wilhelm of Hohenzollern (later Prince of Hohenzollern).
She was called "Mädi" in the family and had a lifelong friendship with her cousin the Archduchess Marie Valerie of Austria.

Question: Who is Princess Maria Teresa Of Bourbon-Two Sicilies (1867–1909)'s maternal grandmother?