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.

His father was the younger brother and heir presumptive of the reigning Greek king, George II, and his mother was the only daughter of Ernest Augustus, Duke of Brunswick, and Princess Victoria Louise of Prussia.

[16][17] On 22 April 1941, Princess Frederica and her two children, Sofia and Constantine, were evacuated to Crete in a British Short Sunderland flying boat along with most of the Greek royal family.

George VI of the United Kingdom opposed the presence of Princess Frederica, who was suspected of having Nazi sympathies,[20] and her children in Britain, but it was decided that Constantine's father and uncle could take up residence in London, where a government-in-exile was set up, while the rest of the family could seek refuge in the then-Union of South Africa.

[21][22] On 27 June 1941, most of the Greek royal family, therefore, set off for South Africa on board the Dutch steamship Nieuw Amsterdam, which arrived in Durban on 8 July 1941.

[27][28] The group subsequently moved several times until they settled in Villa Irene in Pretoria with Prime Minister Jan Smuts, who quickly became a close friend of the exiled Greeks.

Despite their difficult financial circumstances, the family then established friendly relations with several Egyptian personalities, including Queen Farida, whose daughters were roughly the same age as Constantine and his sisters.

[32][33][34] Prince Paul, who was more combative but also more popular than his brother, would have liked to return to Greece as heir to the throne as early as the liberation of Athens in 1944, as he believed that back in his country he would have been quickly proclaimed regent, which would have blocked the way for Damaskinos and made it easier to restore the monarchy.

The accession of Constantine came shortly after the election of centrist George Papandreou as prime minister in February 1964, which ended 11 years of right-wing rule by the National Radical Union (ERE).

[52] Constantine succeeded to the throne at a time when Greek society was experiencing economic and employment growth, but also political crises and violent social protests.

[68][65] Due to Constantine's personal involvement and his clash with Papandreou, the protests -the largest, most persistent and combative since 1944- featured explicitly anti-monarchical slogans and the monarchy turned into a point of contention.

An end to the crisis seemed in sight when on 20 December 1966, Papandreou, ERE leader Panagiotis Kanellopoulos and the king reached a resolution; elections would be held under a straightforward system of proportional representation where all parties participating agreed to compete, and that, in any outcome, the command structure of the army would not be altered.

[72] Tanks rolled through the streets of Athens, rifle shots were heard and military songs were played on the radio until the announcement that "The Hellenic Armed Forces have undertaken the governance of the country" was made public.

[79] From the outset, the relationship between Constantine and the regime of the colonels was an uneasy one, especially when he refused to sign the decree imposing martial law and asked Talbot to flee Greece in an American helicopter with his family.

[78] The presence of the United States Sixth Fleet in the Aegean Sea outraged the junta government, which forced Constantine to get rid of his private secretary, Michail Arnaoutis [el].

[78] Arnaoutis, who had served as the king's military instructor in the 1950s and became his close friend, was generally reviled among the public for his role in the palace intrigues of the previous years.

[78] The king communicated with Konstantinos Karamanlis, who was exiled in Paris and aware of the plot, and attempted to persuade him return to assume the post of prime minister if this movement was successful, but he refused.

[78] They intended to initiate their plan on the day of a military parade scheduled for 28 October, but the junta-installed Chief of the Hellenic Army General Staff, Odysseas Angelis, refused to mobilise the units that Georgios Peridis requested.

[78] But some conspirators were neutralised, such as General Manettas, and Odysseas Angelis informed the public of the plan, asking citizens to obey his orders minutes before telecommunications were cut off.

[78] Constantine, the royal family and Konstantinos Kollias took off in torrential rain from Kavala for exile in Rome, where they arrived at 4 p.m. on 14 December, with their plane having only five minutes of fuel left.

[6] On 24 July, he declared his "deep satisfaction with the initiative of the armed forces in overthrowing the dictatorial regime" and welcomed the advent of Karamanlis as prime minister.

[85] Following the appointment of a civilian government in November 1974 after the first post-junta legislative election, Karamanlis called a referendum, held on 8 December 1974, on whether Greece would restore the monarchy or remain a republic.

The funeral was generally controversial, due to the little empathy generated by Queen Frederica and the royal family, which is why the government authorized him to stay only for six hours in the country.

[90] The British also provided warnings that sympathizers had informed Constantine that a coup would take place in November 1976, led by low-ranking army officers loyal to former dictator Dimitrios Ioannidis.

[95][failed verification] Following this clash between police and protestors in support of Constantine, Mitsotakis made a public statement explaining that the government "had no prior knowledge of the visit and had never agreed to it.

In September 1974, the government of National Salvation, headed by Constantine Karamanlis revoked the junta's decree in anticipation of the referendum that would determine the country's constitution.

In fact, on the basis of the consultative document drafted by Evangelos Venizelos for the Municipality of Corfu to strengthen their claim to Mon Repos,[99] when PASOK returned to power under, it abolished the previous law and replaced it with 2215/1994.

With the compensation, the former king set up the "Anna Maria Foundation" to allocate the funds back to the Greek people for use in "extraordinary natural disasters" and charitable causes.

The Greek government, through then Culture Minister Georgios Voulgarakis, tried to stop the auction, claiming that the items may have been illegally exported from Greece, but the attempt failed.

[127] Constantine never formally renounced his title as King of the Hellenes due to Greek Orthodox anointment tradition, which states that a monarch will never lose their status until their death.