Later , Constantinople was sacked in 1204 by the Catholic armies of the Fourth Crusade , whereas two decades previously the Massacre of the Latins ( i.e. Catholics ) had occurred in Constantinople in 1182 . Thus , by the 12th – 13th centuries , the two sides had become openly hostile , each considering that the other no longer belonged to the Church that was orthodox and catholic . Over time , it became customary to refer to the Eastern side as the Orthodox Church and the Western as the Catholic Church , without either side thereby renouncing its claim to be the truly orthodox or the truly catholic Church
Massacre of the Latins
Massacre of the Latins
Eastern Catholic Churches