Constantine II (Greek: Κωνσταντίνος Βʹ, romanized: Konstantínos II, pronounced [ˌkonsta(n)ˈdinos o ˈðefteros]; 2 June 1940 – 10 January 2023)[1] was the last King of Greece, reigning from 6 March 1964 until the abolition of the Greek monarchy on 1 June 1973.

Constantine was born in Athens as the only son of Crown Prince Paul and Crown Princess Frederica of Greece. Being of Danish descent, he was also born as a prince of Denmark. As his family was forced into exile during the Second World War, he spent the first years of his childhood in Egypt and South Africa. He returned to Greece with his family in 1946 during the Greek Civil War. After Constantine's uncle, George II, died in 1947, Paul became the new king and Constantine the crown prince. As a young man, Constantine was a competitive sailor and Olympian, winning a gold medal in the 1960 Rome Olympics in the Dragon class along with Odysseus Eskitzoglou and George Zaimis in the yacht Nireus. From 1964, he served on the International Olympic Committee.

Constantine acceded as king following his father's death in 1964. Later that year, he married Princess Anne-Marie of Denmark, with whom he had five children. Although the accession of the young monarch was initially regarded auspiciously, his reign saw political instability that culminated in the Colonels' Coup of 21 April 1967. The coup left Constantine, as head of state, with little room to manoeuvre since he had no loyal military forces on which to rely. He thus reluctantly agreed to inaugurate the junta, on the condition that it be made up largely of civilian ministers. On 13 December 1967, Constantine was forced to flee the country, following an unsuccessful countercoup against the junta.

Constantine formally remained Greece's head of state in exile until the junta abolished the monarchy in June 1973, a decision ratified via a referendum in July, which was contested by Constantine. After the restoration of democracy a year later, another referendum was called for December 1974, but Constantine was not allowed to return to Greece to campaign. The referendum confirmed by a majority of almost 70% the abolition of the monarchy and the establishment of the Third Hellenic Republic. Constantine accepted the verdict of the 1974 vote.[2][3] From 1975 until 1978 he was involved in conspiracies to overthrow the government via a coup, which eventually did not materialize. After living for several decades in London, Constantine moved back to Athens in 2013. He died there in 2023 following a stroke.

Description above from the Wikipedia article Constantine II of Greece, licensed under CC-BY-SA, full list of contributors on Wikipedia.