A council or synod, is an assembly of ecclesiastics met to regulate doctrine or discipline. We first hear of such assemblies during the Mon-tanist controversy, about 150 A. d. (Ecumenical councils are convoked from all parts of Christendom, and claim to regulate the affairs of the whole church. Other synods have represented the East and West respectively. Patriarchal, national, and primatial councils represent a whole patriarchate, a nation, or the several provinces subject to a primate, while the bishops and other dignitaries of a province constitute a provincial; the clergy of a diocese under the presidency of the bishop, a diocesan council. Mixed councils during the middle ages dealt with civil as well as ecclesiastical affairs, and were composed of secular persons as well as churchmen. Sometimes, but not always, the lay and ecclesiastical members voted in separate chambers.

The Greek Church recognizes seven general councils - viz.: (1) The first of Nicaea, 325 A. d.; (2) the first of Constantinople, 381; (3) Ephesus, 431; (4) Chalcedon, 451; (5) second of Constantinople, 553; (6) third of Constantinople, 680; (7) second of Nicaea, 787. To these Roman Catholics add: (8) fourth of Constantinople, 869; (9) first Lateran, 1123; (10) second Lateran, 1139; (11) third Lateran, 1179; (12) fourth Lateran, 1215;

13) first of Lyons, 1245; (14) second of Lyons, 1274; (15) Vienne, 1311; (16) Constance, 1414-18, of which Ultramontanes accept only the decrees passed in sessions 1442-45 inclusive and such decrees of earlier sessions as were approved by Martin V.; (17) Basel, 1431 and the following years, oecumenical according to Ultramontanes only till the end of the twenty-fifth session, and even then only in respect of such decrees as were approved by Eugenius IV.; (18) Ferrara-Florence, 1438-42, really a continuation of Basel; (19) fifth Lateran, 1512-17; (20) Trent, 1545-63; (21) Vatican, December 8, 1869, to July 18, 1870, and still unfinished.