The Greek Orthodox Churches are Churches separated from Rome and following the Byzantine Rite, i. e. the rite developed at Constantinople between the fourth and tenth centuries.
The Church of Greece dates back to 1833, when 36 bishops proclaimed their independence of Constantinople and established a Holy Synod; its authority was not recognized until 11 July, 1850, by the œcumenica1 patriarch. At the present time this Church is controlled by a Holy Synod of five members: the Metropolitan of Athens as president and four bishops chosen in regular succession.
Is that the Church you are referring to?
Aieno, did you know the Catholic Church gave the Orthodox Christians the name of Orthodox, which they have usurped?
Peace