Church councils representing the whole church, hence called ecumenical from the Greek word oikoumene (inhabited world). The Roman Catholic Church recognizes twenty-one councils as having been ecumenical. According to canon law, an ecumenical council must be convoked by the pope, and all diocesan bishops of the church must be invited. Its decrees are binding only upon papal ratification, and the rulings of the papacy cannot be appealed to a council. Although in modern Roman Catholic theology councils are held to be subordinate to the papacy, this was not always the case.
Ecumenical councils originated in the Christian, and the early councils were convoked by emperors who summoned the bishops, paid their expenses, and gave their decisions binding force. Whether or not a council was finally accepted as ecumenical was, in fact, based on later recognition by the church rather than on its actual characteristics. Some councils which believed themselves to be ecumenical were later not included in the list of ecumenical councils. Others, such as the Council of Constantinople (381) which was held without the pope's knowledge and which included only Eastern bishops, were later accepted as ecumenical although they did not conform to the modern definition.
There is little agreement among Christians on the number of ecumenical councils. Some churches accept only the first three (Coptic, Armenian, and Syrian). Theand many Protestants accept the first seven, while Luther regarded only the first four as ecumenical. Luther believed the decisions of councils were not infallible since they were subordinate to the Word of God; however, if those decisions were in harmony with God's Word, they deserved respect since they were the expression of the community of believers guided by the . He therefore respected the decisions of the early councils, but rejected the medieval ones because he felt they had introduced superstitions and errors into Christian teaching. The councils considered by the Roman Church as ecumenical can be divided into four groups:
(1) The first eight, which were convoked by emperors and normally had representation from both Eastern and Western clergy: Nicea I (325); Constantinople I (381); Ephesus (431); Chalcedon (451); Constantinople II (553); Constantinople III (680-81); Nicea II (787); Constantinople IV (869-70).
(2) The seven medieval councils which were convoked and controlled by the papacy: Lateran I (1123); Lateran II (1139); Lateran III (1179); Lateran V (1215); Lyon I (1245); Lyon II (1274); Vienne (1311-12).
(3) Three late medieval councils which were held during the period when the conciliar movement was challenging the power of the papacy and which witnessed both the initial success of the movement and its final defeat: Constance (1414-18); Basle-Ferrara- Florence (1431-37); Lateran IV (1512-17).
(4) The last three councils which were all convoked by popes and which best fit the characteristics described by modern Roman Catholic theology: Trent (1545-63); Vatican I (1869-70);(1962-65).
See entries under individual councils.