Orientales ecclesias
With the encyclical Orientales ecclesias (Latin: The Eastern Churches) of December 15, 1952, Pope Pius XII. “On the Persecution of the Oriental Church ”.
The occasion of this encyclical is the imprisonment (1948) and the martyr's death (October 5, 1952) of the Bulgarian Bishop Vincentius Eugenio Bossilkoff from Nicopoli , the eponymous diocese of Nicopolis . Pius XII. expressed solidarity with the Eastern Churches and mentioned the people
"Who persevere in the faith and oppose the enemies of Christianity with the same indomitable strength with which they resisted their ancestors at the time."
He praised the fact that they had shown the courage to remain faithful to the Pope in Rome and to their pastors.