Assemblies of bishops and other ecclesiastical representatives of the whole world whose decisions on doctrine, discipline, etc. are considered binding on all Christians. According to RC canon law, the Pope alone has the right to convene a Council, to preside over it (in person or through deputies), and to approve its decrees. Under certain conditions, the college of bishops gathered in an Oecumenical Council is held to possess infallible teaching authority.
Seven Councils are held both in E. and W. to be oecumenical, namely those of Nicaea V (325), Constantinople V (381), Ephesus (431), Chalcedon (451), Constantinople II (553), Constantinople III (680–1), and Nicaea II (787). The RC Church reckons the following Councils as also possessing oecumenical authority: Constantinople IV (869–70), Lateran V (1123), Lateran II (1139), Lateran III (1179), Lateran IV (1215), Lyons V (1245), Lyons II (1274), Vienne (1311–2), Constance (1414–7), Basle-Florence (1431–45), Lateran V (1512–7), Trent (1545–63), Vatican V (1869–70), and Vatican II (1962–5).