The Greek Orthodox Ecumenical Patriarch of Constantinople stil today has his residence in Istanbul .
Two out of the five centers ( Patriarchates ) of the ancient Pentarchy are in Turkey : Constantinople ( Istanbul ) and Antioch ( Antakya ) .
The Greek Orthodox Ecumenical Patriarch of Constantinople stil today has his residence in Istanbul .
Two out of the five centers ( Patriarchates ) of the ancient Pentarchy are in Turkey : Constantinople ( Istanbul ) and Antioch ( Antakya ) .