Œcumenical Councils. There are twenty-one recognised, nine Eastern and twelve Western.
The Nine Eastern: (1) Jerusalem; (2 and 8) Nice, 325, 787; (3, 6, 7, 9) Constantinople, 381, 553, 680, 869; (4) Ephesus, 431; (5) Chalcēdon, 451.
The Twelve Western: (10, 11, 12, 13, 19) Latʹeran, 1123, 1139, 1179, 1215, 1517; (14, 15) Synod of Lyon, 1245, 1274; (16) Synod of Vienne, in Dauphine, 1311; (17) Constance, 1414; (18) Basil, 1431–1443; (20) Trent, 1545–1563; (21) Vatican, 1869.
325 of Nice, against the Arians.
381 of Constantinople, against “heretics.”
431 of Ephesus, against the Nestorians and Pelagians.
451 of Chalceʹdon, when Athanasius was restored.
553 of Constantinople, against Origen.
680 of Constantinople, against the Menothĕlites (4 syl.).
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