His late and former Majesty's life saw much turbulence, not least that which resulted in him and his family fleeing Greece in 1967 and the formal abolition of the Monarchy in 1973.
A competitive sailor and Olympian, Constantine married his distant cousin, HRH Princess Anne-Marie of Denmark in 1964, himself being a Prince of Denmark being a descendant of HM King Christian IX. Constantine's forefather, HRH Prince William of Denmark, second son of King Cristian IX, had been elected King of Greece in 1863 and had reigned as HM King George I of the Hellenes.
Constantine has been succeeded as head of the Greek Royal Family by his eldest son Crown Prince Pavlos. As the Monarchy in Greece was formerly abolished, Pavlos cannot be called King unless the Monarchy is restored.
The Heraldry of the Greek Royal Family was covered in a previous Blog.
My condolences and sympathies go to Her Majesty Queen Anne-Marie and the Greek Royal Family.