Title: Princess Maria of Greece and Denmark
Content:  Princess Maria of Greece and Denmark (Μαρία) (Мария Георгиевна; 3 March [ O.S. 20 February] 1876 – 14 December 1940) was a daughter of King George I of Greece and his wife Grand Duchess  Olga Constantinovna of Russia. She was a sister of King Constantine I of Greece and a first cousin of Tsar Nicholas II of Russia. Born as a princess of Greece and Denmark, she was educated in Athens by private tutors. Her father instilled in her a great love for Greece and throughout her life, she remained a fervent patriot. She married Grand Duke George Mikhailovich of Russia, her first cousin once removed, who courted her for five 
Title: Princess Marina of Greece and Denmark
Content:  Princess Marina was born on 13 December 1906 in Athens, Greece, during the reign of her paternal grandfather, George I of Greece. She was the third and youngest daughter of Prince Nicholas of Greece and Denmark, and his wife Grand Duchess Elena Vladimirovna of Russia. Her father was the third son of George I of Greece and Queen Olga, while her mother was the only daughter of Grand Duke Vladimir Alexandrovich and Grand Duchess Maria Pavlovna of Russia. Her father was a grandson of Christian IX of Denmark, while her mother was a granddaughter of Emperor Alexander II of Russia. Princess 
Title: Princess Maria of Greece and Denmark
Content:  Princess Maria of Greece and Denmark was born on 3 March 1876 at the Royal Palace in Athens. She was the fifth child and second daughter of King George I of Greece and Grand Duchess Olga Constantinovna of Russia. Maria's father was born a Danish prince. Thus, the Greek royal family was part of the Danish. Princess Maria, nicknamed "Greek Minnie" to tell her apart from the elder "Minnie", her paternal aunt (Empress Maria Feodorovna of Russia), grew up as part of a large family of eight children. One sister, named Olga, died in childhood, but she had five brothers:  (Constantine, George, Nicholas, Andrew, Christopher) and one surviving sister: Alexandra. King George and Queen Olga were devoted parents who provided a happy, homely environment for their children. The Greek royal family was not wealthy by royal standards and they lived with simplicity. Throughout the 
Title: Princess Maria-Olympia of Greece and Denmark
Content:  Princess Maria-Olympia of Greece and Denmark (born 25 July 1996) is a fashion model, socialite and member of the Greek royal family. She is the oldest child and only daughter of Pavlos, Crown Prince of Greece and his wife, Marie-Chantal Miller. Her paternal grandparents are Constantine II of Greece and Anne-Marie of Denmark, who were the last King and Queen of the Hellenes, while her maternal grandfather is duty free entrepreneur Robert Warren Miller.
Title: Monarchy of Denmark
Content:  Most members of the Greek Royal Family are members of the Danish Royal Family and bear the title of Prince or Princess of Greece and Denmark, as descendants of Christian IX of Denmark. Due to the morganatic status of her marriage, Marina, Consort of Prince Michael, and their children, Princesses Alexandra and Olga, are exceptions.
Title: Danish royal family
Content: Marina, consort of Prince Michael of Greece and Denmark ; Princess Alexandra, Mrs. Mirzayantz ; The Duchess of Apulia Queen Sofia of Spain (King Constantine's sister and Queen Anne-Marie's sister-in-law) Most of the members of the deposed royal family of Greece hold the title of Prince or Princess of Greece and Denmark with the qualification of His or Her Highness, pursuant to the Royal Cabinet Order of 1774 and as agnatic descendants of George I of Greece, who, as the son of the future King Christian IX of Denmark, was (and remained) a "Prince of Denmark" prior to his accession to the throne 
Title: Princess Marina of Greece and Denmark
Content:  Princess Marina of Greece and Denmark (Μαρίνα; 13 December 1906 – 27 August 1968), later Princess Marina, Duchess of Kent, was a Greek princess by birth and a British princess by marriage. She was a daughter of Prince Nicholas of Greece and Denmark and Grand Duchess Elena Vladimirovna of Russia, and a granddaughter of King George I and Queen Olga of Greece. Princess Marina married Prince George, Duke of Kent, fourth son of King George V and Queen Mary, in 1934. They had three children: Prince Edward, Princess Alexandra, and Prince Michael. The Princess was widowed in 1942, when her husband was killed in a plane crash on active service. In later life she carried out many royal engagements, including the independence celebrations for Ghana and Botswana.
Title: Princess Maria of Greece and Denmark
Content:  After the wedding, the couple boarded the Greek royal yacht and sailed to the Bay of Naples. They spent their honeymoon in Italy and traveled around Austria-Hungary. From Vienna, they arrived in Russia by the way of Warsaw. Princess Maria of Greece, known in Russia as Grand Duchess Maria Georgievna of Russia, was welcomed by the Romanovs as one of their own. Her mother, Queen Olga of Greece, was a Russian Grand Duchess by birth, a first cousin of Tsar Alexander III of Russia. Maria's father, King George of Greece, was Empress Maria Feodorvna's favorite brother. Maria was a first cousin of Tsar Nicholas II, who 
Title: Princess Maria-Olympia of Greece and Denmark
Content:  Princess Maria-Olympia of Greece and Denmark was born on 25 July 1996 at Weill Cornell Medical Center in New York City to Pavlos, Crown Prince of Greece and his wife, Marie-Chantal. She was baptized in the Greek Orthodox Church by Patriarch Bartholomew I of Constantinople at the Church of St. George in Istanbul, Turkey on 22 December 1996. Her godparents are her paternal aunt Princess Alexia of Greece and Denmark, her maternal aunt Pia Getty, her grandfather's second cousin The Prince of Wales, and Prince Michael of Greece and Denmark. Her family relocated to London, where she spent most of her childhood. She is the older sister of Prince Constantine-Alexios, Prince Achileas-Andreas, Prince Odysseas-Kimon, and Prince Aristidis-Stavros. The princess herself uses the name Olympia in every-day life. Olympia of Greece attended her first couture show around the age of 11 in Rome together with her parents. She studied art history, theatre, photography, and graphic design while in boarding school in Switzerland with hopes of pursuing a career in art or fashion. She interned in Dior's couture department, at the age of 17.
Title: Greek royal family
Content:  Constantine II ; Prince Michael of Greece and Denmark and Marina, his consort (grandson of King George I and King Constantine II's first cousin-once-removed and his wife) ; Princess Alexandra, born on October 15, 1968 ; Princess Olga Isabelle, Duchess of Aosta, born on November 17, 1971 ; The descendants of Prince Philip of Greece and Denmark (grandson of King George I) (1921–2021), who married Elizabeth II of the United Kingdom. ; The descendants of the daughters of Prince Andrew of Greece and Denmark (Prince Philip's sisters) which were: Princess Margarita of Greece and Denmark, Princess Theodora of Greece and Denmark (1906–1969) and Princess Sophie of Greece and Denmark ; The descendants 

Question: Who is the father of Princess Maria of Greece and Denmark?
Answer: George I of Greece.
George I.