Complex sentence: This action brought immediate protest from the Estonian-born Patriarch Alexei II of the Moscow Patriarchate, which regarded the Estonian church as being part of its territory, and the Patriarch of Moscow temporarily removed the name of the Ecumenical Patriarch from the diptychs.
Split into simpler sentences: This action brought immediate protest from the Estonian-born Patriarch Alexei II of the Moscow Patriarchate, which regarded the Estonian church as being part of its territory. The Patriarch of Moscow temporarily removed the name of the Ecumenical Patriarch from the diptychs.