This is a list of the heads of government of the modern Greek state, from its establishment during the Greek Revolution to the present day. Although various official and semi-official appellations were used during the early decades of independent statehood, the title of prime minister has been the formal designation of the office at least since 1843. On dates, Greece officially adopted the Gregorian calendar on 16 February 1923 (which became 1 March). All dates prior to that, unless specifically denoted, are Old Style.