question: Princess Maria-Olympia is the only daughter of the eldest son and second child of Constantine II, who was the last king of Greece from 1964 until when?
answer: 1973
context: Title: Pavlos, Crown Prince of Greece
  Passage: Pavlos, Crown Prince of Greece, {'1': ", '2': ", '3': 'RE', '4': "} (Greek: Παύλος ; born 20 May 1967) is the eldest son and second child of Constantine II, the last King of Greece from 1964 to 1973 and his wife, Anne-Marie of Denmark.  Pavlos was heir apparent to the throne of Greece and was its crown prince from birth, remaining so during his father's reign until the monarchy's abolition.
  Title: Princess Friederike of Hanover
  Passage: Princess Friederike of Hanover ("German: Friederike Elisabeth Viktoria-Luise Alice Olga Theodora Helena, Prinzessin von Hannover, Prinzessin von Großbritannien und Irland, Herzogin zu Braunschweig-Lüneburg"), (born 15 October 1954 at Salem, Baden-Württemberg, Germany) is the youngest child and only daughter of Prince George William of Hanover and his wife Princess Sophie of Greece and Denmark, sister of Prince Philip, Duke of Edinburgh.  Queen Sofia of Spain and Constantine II of Greece are paternal first cousins and maternal first cousins once removed of Friederike, while she is a first cousin, through her mother, to Charles, Prince of Wales and a goddaughter of Elizabeth II of the United Kingdom.
  Title: Princess Maria-Olympia of Greece and Denmark
  Passage: Princess Maria-Olympia of Greece and Denmark (born 25 July 1996 in New York City) is the oldest child and only daughter of Pavlos, Crown Prince of Greece and Marie-Chantal, Crown Princess of Greece.  Her paternal grandparents are Constantine II and Anne-Marie of Denmark, who were the last King and Queen of the Hellenes.
  Title: Greek royal family
  Passage: The Greek royal family (Greek: Ελληνική Βασιλική Οικογένεια) is a branch of the House of Glücksburg that reigned in Greece from 1863 to 1924 and again from 1935 to 1973.  Its first monarch was George I, the second son of King Christian IX of Denmark.  He and his successors styled themselves "Kings of the Hellenes".  Most members of the dynasty (aside from the last king to reign, Constantine II and his queen consort, Anne-Marie of Denmark) hold the title "Prince or Princess of Greece and Denmark" with the style "Royal Highness", except Marina, Consort of Prince Michael, and their daughters Princess Alexandra and Princess Olga.
citations: Princess Maria-Olympia of Greece and Denmark Pavlos, Crown Prince of Greece