Phyletism
Phyletism or ethnophyletism (from Greek ἔθνος ethnos "nation" and φυλετισμός phyletismos "tribalism") is the principle of nationalities applied in the ecclesiastical domain: in other words, the conflation between Church and nation. The term ethnophyletismos designates the idea that a local autocephalous Church should be based not on a local [ecclesial] criterion, but on an ethnophyletist, national or linguistic one. It was used at the Holy and Great [Μείζων Meizon "enlarged"] pan-Orthodox Synod in Constantinople on 10 September 1872 to qualify “phyletist (religious) nationalism,” which was condemned as a modern ecclesial heresy: the Church should not be confused with the destiny of a single nation or a single race.
History
After their emancipation from Ottoman rule, the Balkan churches freely developed both their national identities and their religious life. Theological faculties were created in Athens, Belgrade, Sofia, and Bucharest. The Romanian Orthodox Church introduced the full cycle of the liturgical offices in vernacular Romanian. But these positive developments were often marred by nationalistic rivalries.