King Constantine II

He succeeded his father Paul in March 1964, being styled Konstantinos II, King of the Hellenes. Although the accession of the young monarch was initially regarded auspiciously, his reign soon became controversial: Constantine's involvement in the Apostasia of July 1965 made him unpopular in broad parts of the population and aggravated the ongoing political instability that culminated in the Colonels' coup of 21 April 1967. The coup stood on scant legitimate ground until Constantine, as head of state, agreed to swear-in the putschist government, thereby legitimizing it; this act became the subject of much criticism. On 13 December 1967, he was forced to flee the country following an abortive counter-coup against the junta, although he remained de jure head of state until 1 June 1973, when the junta abolished the monarchy and declared a Republic. This abolition was confirmed after the fall of the junta by a plebiscite on 13 December 1974, which established the Third Hellenic Republic.