The head of the Orthodox Church is Jesus Christ. The spiritual
leaders are the four Ancient Patriarchates (ie. Constantinople,
Alexandria, Antioch, Jerusalem) followed by the leaders of the
"Autocephalous" (self-governing) churches, such as Moscow, Greece,
Serbia, etc. The Orthodox Church has no pope as the sole leader.
The highest authority in the Orthodox Church is an Ecumenical
Council (or Synod) that consists of the spiritual leaders (or their
representatives) from the whole Orthodox world.