During the Councils of Constantinople (381) and Chalcedon (451), the Church established five patriarchates: in alphabetic order they are the Patriarchates of Alexandria, Antioch, Constantinople, Jerusalem and Rome.
Emperor Justinian (527-565) classified the Patriarchs of the Orient in the following order: Constantinople, Alexandria, Antioch ad Jerusalem.
It is only after the schism of 1054 that the Ecumenical Patriarch of Constantinople began to use the title of “primus inter pares”, “the first among his peers”.
This title is primarily honorific. However, the Ecumenical Patriarch does have two privileges:
1. the right to convoke and preside at inter-confessional meetings (including various Churches)
2. the right to intervene in order to find a solution during a contradictory debate in a local Orthodox church, depending on his jurisdiction or not.
Despite having the title of “First among equals”, in Jerusalem, precedence remains that of the Greek Orthodox Patriarch of the place, now Theophilos III, who can invite the Ecumenical Patriarch to take the place of honor.