On 3 September 1843, the infantry, led by Colonel Dimitrios Kallergis and the Revolutionary captain Ioannis Makriyannis, assembled in the square in front of the palace in Athens.
Eventually joined by much of the population of the small capital, the rebellion refused to disperse until the king agreed to grant a constitution.
Nonetheless, on 24 June 1925, officers loyal to Theodoros Pangalos, fearing that the political instability was putting the country at risk, overthrew the government in a coup and violated the Constitution.
A more conservative Constitution was passed in 1952, which imposed restrictions on basic human rights and banned the Communist Party of Greece (KKE).
Thereby, the Revolutionary Council of Stylianos Pattakos, George Papadopoulos and Nikolaos Makarezos made a brief appearance to cause a Resolution to be published in the Government Gazette, appointing another member to the military administration, Major General Georgios Zoitakis, as Regent.
King Constantine was officially retained as head of state, though he would not be allowed to return until the first parliamentary election unless the government recalled him sooner.
Many of the guarantees of civil rights were suspended, and elections were postponed until the "Revolution of April 21" (as the coup was called) had reformed the "Greek mentality."
A new Constitution was drafted, providing for a popularly elected president with wide-ranging powers, effectively establishing a presidential republic.
After the hard-liners' coup on 25 November 1973 deposed Papadopoulos, the regime retained the trappings of the Republic, but not the 1973 constitution; it reverted to exclusively military control until its final collapse in the wake of the Cyprus crisis in August 1974.
In the meantime, the functions of the king were to be discharged by the incumbent President of the Republic General Phaedon Gizikis who was appointed by the Ioannides' short-lived regime as a nominal figurehead.