Complex sentence: The Serbian Patriarchate, established in 1557 had a considerably part of the Ottoman Empire under its jurisdiction, until it was taken over by the Greek Phanariotes in the 18th century and finally abolished and joined to the Ecumenical Patriarchate in 1766.
Split into simpler sentences: The Serbian Patriarchate established in 1557 had a considerable part of the Ottoman Empire under its jurisdiction until it was taken over by the Greek Phanariotes in the 18th century. It was finally abolished and joined to the Ecumenical Patriarchate in 1766.