Princess Luisa Cristina of Savoy
Princess Luisa Cristina of Savoy (27 July 1629 – 12 May 1692) was a Princess of Savoy by birth and the eldest daughter of Victor Amadeus I, Duke of Savoy.
She married her uncle Prince Maurice of Savoy but had no children.
She was the owner of the future "Villa della Regina".
She was a first cousin of Louis XIV of France and Charles II of England.
Princess Maria Pia of Bourbon-Parma
Princess Maria Pia of Bourbon- Parma( née Princess Maria Pia of Savoy; born 24 September 1934) is the eldest daughter of Umberto II of Italy and Marie- José of Belgium.
She is the older sister of Princess Maria Gabriella of Savoy, Vittorio Emanuele, Prince of Naples, and Princess Maria Beatrice of Savoy.
Princess Mafalda of Savoy
Princess Mafalda of Savoy (2 November 1902 – 27 August 1944) was the second daughter of King Victor Emmanuel III of Italy and his wife Elena of Montenegro.
The future King Umberto II of Italy was her younger brother.
René of Savoy
René of Savoy( 1473 – 31 March 1525) was a French nobleman and soldier.
He was count of Villars( 1497) and of Tende( 1501).
Known as" the Great Bastard of Savoy", he was the illegitimate son of Philip II, Duke of Savoy and Libera Portoneri- this made him the originator of the Savoie- Villars( or Savoie- Tende) branch of the House of Savoy.
Victor Amadeus II, Prince of Carignano
Victor Amadeus of Savoy (31 October 1743 – 10 September 1780) was a member of the House of Savoy and Prince of Carignano.
He was the brother of the murdered "princesse de Lamballe" and grandfather of King Charles Albert of Sardinia.
Yolande Louise of Savoy
Yolande Louise of Savoy( 1487–1499), was a Duchess Consort of Savoy; married to Philibert II, Duke of Savoy.
Cecile of Baux
Cecile of Baux( 1230 – 1275), was a Countess Consort of Savoy; married in 1244 to Amadeus IV, Count of Savoy.
She was the daughter of Barral of Baux and his wife, Sibylle d'Anduze.
She was the Regent of Savoy during the minority of her son, Boniface, Count of Savoy, from 1253 until 1259.
Mafalda von Hessen
Mafalda Margarethe Prinzessin von Hessen( born 6 July 1965), known also as Princess Mafalda of Hesse, is a German aristocrat and fashion designer.
She is the eldest child of Moritz, Landgrave of Hesse and Princess Tatiana of Sayn- Wittgenstein- Berleburg.
Elena of Montenegro
Princess Elena of Montenegro, or more commonly known as Queen Elena of Italy (8 January 1873 – 28 November 1952) was the daughter of King Nicholas I of Montenegro and his wife, Milena Vukotić.
As wife of Victor Emmanuel III of Italy, she was Queen of Italy from 1900 until 1946, Empress consort of Ethiopia from 1936 until 1941 and Queen consort of the Albanians from 1939 until 1943.
Amedeus Alexander of Savoy
Amedeus Alexander of Savoy (5 October 1754 – 29 April 1755) was a Prince of Savoy by birth, son of the king of Sardinia Victor Amadeus III of Savoy and his wife Maria Antonietta of Spain (daughter of Philip V of Spain).

Question: Who is Princess Mafalda Of Savoy's maternal grandfather?
Answer: Nicholas I of Montenegro