Duke of Castel Duino
The Dukes of Castel Duino are a noble family in Italy descending from the Bohemian line of the Princely House of Thurn and Taxis.
The title was created along with the additional title of Principe della Torre e Tasso in 1923 for Prince Alexander of Thurn and Taxis following his naturalisation in Kingdom of Italy.
The second duke, Raimundo, married Princess Eugénie of Greece and Denmark a member of the Greek Royal Family.
The seat of the family is Duino Castle in Duino in the Province of Trieste, Friuli- Venezia Giulia.
Princess Eugénie of Sweden
Princess Eugénie of Sweden and Norway( Charlotta Eugenia Augusta Amalia Albertina; 24 April 1830 – 23 April 1889) was a member of the royal House of Bernadotte and a philanthropist and amateur artist.
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 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 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.
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.
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 Marie Bonaparte
Princess Marie Bonaparte (2 July 1882 – 21 September 1962), known as Princess George of Greece and Denmark upon her marriage, was a French author and psychoanalyst, closely linked with Sigmund Freud.
Her wealth contributed to the popularity of psychoanalysis, and enabled Freud's escape from Nazi Germany.
Marie Bonaparte was a great-grandniece of Emperor Napoleon I of France.
She was the only child of Prince Roland Bonaparte (19 May 1858 – 14 April 1924) and Marie-Félix Blanc (1859–1882).
Her paternal grandfather was Prince Pierre Napoleon Bonaparte, son of Lucien Bonaparte, 1st Prince of Canino and Musignano, Napoleon's rebellious younger brother.
For this reason, despite her title Marie was not a member of the dynastic branch of the Bonapartes who claimed the French imperial throne from exile.
Her maternal grandfather was François Blanc, the principal real-estate developer of Monte Carlo.
It was from this side of her family that Marie inherited her great fortune.
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.

Question: What is the date of death of Princess Eugénie Of Greece And Denmark's mother?
Answer: 21 September 1962