The terms Apostasia (Greek: Αποστασία, "Apostasy") or Iouliana (Greek: Ιουλιανά, "July events") or the Royal Coup (Greek: Το Βασιλικό Πραξικόπημα To Vasiliko Praxikopima) are used to describe the political crisis in Greece that centred on the resignation, on 15 July 1965, of Prime Minister Georgios Papandreou and the appointment, by King Constantine II, of successive prime ministers from Papandreou's own party, the Center Union, to replace him. Those defectors from the Center Union were branded, by Papandreou's sympathisers, as the Apostates ("renegades"). The Apostasia heralded a prolonged period of political instability, which weakened the fragile post-Civil War order and ultimately led to the establishment of a military regime in 1967.