The ecumenical councils are the councils of Church authorities accepted by the Church as official. Roman Catholics recognize the following 21 ecumenical councils (listed with their starting dates). The Orthodox Church recognizes only the first seven councils and the continuation of the 3rd Constantinople (the Trullan Synod). The purpose of the first eight councils was to determine whether specific theological concepts were orthodox or heretical. The remaining councils, all held in Western Europe, have dealt chiefly with Church discipline. Two of them, 2nd Lyons and Ferrara-Florence, attempted to reconcile the Eastern and Western Churches. In the Great Schism the conciliar theory developed, which held that an ecumenical council was superior to the pope; this theory was in its heyday at the Council of Constance. The 21st ecumenical council (2nd Vatican), called by Pope John XXIII, advocated the reunion of all Christians with the Church of Rome.

(1) 1st Nicaea, 325
(2) 1st Constantinople, 381
(3) Ephesus, 431
(4) Chalcedon, 451
(5) 2nd Constantinople, 553
(6) 3rd Constantinople, 680
(7) 2nd Nicaea, 787
(8) 4th Constantinople, 869
(9) 1st Lateran, 1123
(10) 2nd Lateran, 1139
(11) 3rd Lateran, 1179
(12) 4th Lateran, 1215
(13) 1st Lyons, 1245
(14) 2nd Lyons, 1274
(15) Vienne, 1311
(16) Constance, 1414
(17) Basel and Ferrara-Florence, 1431, 1438
(18) 5th Lateran, 1512
(19) Trent, 1545
(20) 1st Vatican, 1869
(21) 2nd Vatican, 1962