On his father's death, Constantine II ascended the throne as King of Hellenes on 6 March 1964. In September 1964 he married Princess Anne Marie of Denmark. A crisis soon developed between the king and Prime Minister Georgios Papandreou over royal prerogatives, especially the king's leadership of the Greek armed forces. On 15 July 1965 Constantine II dismissed Papandreou. The king then appointed a succession of interim prime ministers before the May 1967 elections, which Papandreou's Center Union Party was sure to win. To forestall this, Constantine and his circle planned a military coup, but before the generals could orchestrate it, on 21 April 1967 another military group of younger officers led by Georgios Papadoupoulos executed Plan prometheus, a North Atlantic Treaty Organization (NATO) operation to forestall a communist takeover. The colonels in this group seized power and established a military dictatorship in Greece.
On 13 December 1967, Constantine attempted an unsuccessful countercoup, but the majority of the army remained loyal to the new ruling military junta. The next day Constantine and his family fled abroad, first to Rome and then to London. At first the colonels claimed that Constantine was free to return to Greece, but the king refused to subordinate himself to the ruling regime, and on 1 June 1973 Papadoupoulos abolished the monarchy. A referendum held on 29 June 1973 supported the regime's decision. After the fall of the dictatorship in July 1974, the new democratic government, led by Konstantinos Karamanlis, held a referendum in December 1974 that rejected the monarchy by an overwhelming majority. In April 1994 the Greek government stripped Constantine of his citizenship and seized his properties. Constantine currently resides with his family in London.
Lucian N. Leustean
Close, David H. Greece since 1945: Politics, Economy and Society. Edinburgh and London: Pearson Education, 2002.