Princess Margarita of Greece and Denmark
Princess Margarita of Greece and Denmark (18 April 1905 – 24 April 1981) was the eldest child and daughter of Prince Andrew of Greece and Denmark and Princess Alice of Battenberg.
She was the first great-great-grandchild of Queen Victoria, and the eldest sister of Prince Philip, Duke of Edinburgh.
Philipp, Prince of Hohenlohe-Langenburg
Philipp, 10th Prince of Hohenlohe- Langenburg( Philipp Gottfried Alexander; born 20 January 1970 in Crailsheim, West Germany), is the middle child and only son of Kraft, Prince of Hohenlohe- Langenburg and his first wife, Princess Charlotte of Croÿ.
Upon the death of his father in 2004, he became the titular Prince of Hohenlohe- Langenburg.
He is a grandson of Princess Margarita of Greece and Denmark, and a grandnephew of Prince Philip, Duke of Edinburgh.
Anne, Princess Royal of the United Kingdom is one of his godmothers.
Princess Elizabeth of Greece and Denmark
Princess Elisabeth of Greece and Denmark( 24 May 1904 – 11 January 1955) was the middle daughter of Prince Nicholas of Greece and Grand Duchess Elena Vladimirovna of Russia.
Princess Theodora of Greece and Denmark (1906–1969)
Princess Theodora of Greece and Denmark( 30 May 1906 – 16 October 1969) was the second child and daughter of Prince Andrew of Greece and Denmark and Princess Alice of Battenberg, and the second eldest sister of Prince Philip, Duke of Edinburgh.
Prince Andrew of Greece and Denmark
Prince Andrew of Greece and Denmark (– 3 December 1944) of the House of Schleswig-Holstein-Sonderburg-Glücksburg, was the seventh child and fourth son of King George I of Greece and Olga Constantinovna of Russia.
He was a grandson of Christian IX of Denmark and father of Prince Philip, Duke of Edinburgh.
He was from birth a prince of both Denmark and Greece by virtue of his patrilineal descent.
He began military training at an early age, and was commissioned as an officer in the Greek army.
His command positions were substantive appointments rather than honorary, and he saw service in the Balkan Wars.
In 1913, his father was assassinated and Andrew's elder brother, Constantine, became king.
Dissatisfaction with his brother's neutrality policy during World War
I led to his brother's abdication and most of the royal family, including Andrew, was exiled.
On their return a few years later, Andrew saw service as Major General in the Greco-Turkish War (1919–1922), but the war went badly for Greece, and Andrew was blamed, in part, for the loss of Greek territory.
He was exiled for a second time in 1922, and spent most of the rest of his life in France.
By 1930, he was estranged from his wife, Princess Alice of Battenberg.
His only son, Prince Philip, served in the British navy during World War II, while all four of his daughters were married to Germans, three of whom had Nazi connections.
Separated from his wife and son by the effects of the war, Andrew died in Monte Carlo in 1944.
He had seen neither of them since 1939.
Princess Eugénie of Greece and Denmark
Princess Eugénie of Greece and Denmark( 10 February 1910 – 13 February 1989) was the youngest child and only daughter of Prince George of Greece and Denmark and his wife, Princess Marie Bonaparte, daughter of Marie- Félix Blanc and Prince Roland Bonaparte, a great- nephew of Napoleon I.
Her father was the second son of George I of Greece and Olga Constantinovna of Russia.
As a cousin of the bridegroom, she was a leading guest at the 1947 wedding of Princess Elizabeth and Philip, Duke of Edinburgh.
She authored" Le Tsarevitch, Enfant Martyr", a biography of Aleksey Nikolaevich, Tsarevich of Russia, written in French, which was published in 1990.
Princess Irene of Greece and Denmark
Princess Irene of Greece and Denmark( born 11 May 1942) is the youngest child and second daughter of King Paul of Greece and his wife Princess Frederika of Hanover.
She is the younger sister of Queen Sofía of Spain and of the deposed King Constantine II of Greece and maternal aunt of Felipe VI of Spain.
Princess Irene, Duchess of Aosta
Princess Irene of Greece and Denmark( 13 February 1904 – 15 April 1974) was the fifth child and second daughter of Constantine I of Greece and his wife, the former Princess Sophie of Prussia.
She was a member of the royal families of Greece and Italy.
From 1941 to 1943 she was also officially Queen Consort of Croatia.
Princess Anastasia of Greece and Denmark
Princess Anastasia of Greece and Denmark ("née" Nonie May Stewart; 20 January 1878 – 29 August 1923) was an American-born heiress and member of the Greek Royal Family.
She was married to Prince Christopher of Greece and Denmark, the youngest child of King George I of Greece and his consort, Grand Duchess Olga Constantinovna of Russia, but was created a princess "suo jure".
Princess Margarita of Baden
Princess Margarita of Baden(" Margarete Alice Thyra Viktoria Marie Louise Scholastica"; 14 July 1932 – 15 January 2013) was the only daughter of Berthold, Margrave of Baden, and Princess Theodora of Greece and Denmark.
She was the eldest niece of Queen Elizabeth II and Prince Philip, Duke of Edinburgh.

Question: Who is the paternal grandfather of Princess Margarita Of Greece And Denmark?
Answer: George I of Greece