21 ECUMENICAL COUNCILS

• 1. First Council of Nicea (325)
• 2. First Council of Constantinople (381)
• 3. Council of Ephesus (431)
• 4. Council of Chalcedon (451)
• 5. Second Council of Constantinople (553)
• 6. Third Council of Constantinople (680-681)
• The "Quinsext" Council in Trullo (692)
• 7. Second Council of Nicea (787)
• 8. Fourth Ecumenical Council of Constantinople (869–870)
• 9. First Lateran Council (1123)
• 10. Second Lateran Council (1139)
• 11. Third Lateran Council (1179)
• 12. Fourth Lateran Council (1215)
• 13. First Council of Lyon (1245)
• 14. Second Council of Lyon (1274)
• 15. Council of Vienne (1311–1312)
• 16. Council of Constance (1414–1418)
• 17. Council of Basel-Ferrara-Florence (1431–1445)
• 18. Fifth Lateran Council (1512–1517)
• 19. Council of Trent (1545-1563)
• 20. First Vatican Council (1869-1870)
• 21. Second Vatican Council (1962–1965)