The Quinisext Ecumenical Council was held in 692 and is regarded as supplementing the Fifth Ecumenical Council of 553 and the Sixth Ecumenical Council of 681. This council is often referred to as the Council in Trullo. The work of the council was mainly legislative, ratifying 102 canons and decisions of the two earlier Ecumenical Councils.
The Quinisext Council was convened in 692 by Justinian II in Constantinople. It is often referred to as the Council in Trullo because the sessions were held in the same domed room where the Sixth Council was conducted. Both the Fifth and the Sixth Councils had adjourned without drawing up disciplinary canons. The 692 council was convened with the intention to complete the work of the earlier councils in this respect, and it was from this aspect that it took the name Quinisext, i.e. Fifth-Sixth Council. (Latin:Concilium Quinisextum, Koine Greek: Πενθέκτη Σύνοδος - Penthekte Synodos).
Two hundred and eleven bishops attended the council, all from the Eastern Roman Empire. Basil of Gortyna in Illyria/Crete, however, belonged to the Church of Rome and claimed that he represented the Roman Church, though no evidence exists that he was appointed as representative. Later, Pope Sergius of Rome refused to sign the canons, citing them as “lacking authority”, when they were sent to him for signature. The Western Church never recognized the 102 disciplinary canons of this council, although later statements by some of the bishops of Rome, notably Popes Constantine and Hadrian I, seem to show a certain acceptance. Pope John VII stated that he accepted all those canons which did not contradict the true faith, good morals, and decrees of Rome. The Orthodox Church considers this council as ecumenical and adds its canons to the decrees of the Fifth and Sixth Councils.
Many of the canons were reiterations of previously passed canons. Among the new canons, most were intended to bring the practices of the worldwide Church to a common standard, and this common standard was largely in accord with the disciplinary rules of Constantinople and therefore quite different from the customs of the Western Church. Many Western customs were condemned, with some modern authors claiming this included "every little detail of difference" (Fortescue).
Among the practices of the Western Church thus condemned were the practice of celebrating liturgies on weekdays in Lent (rather than having pre-sanctified liturgies); of fasting on certain Saturdays during the year; of omitting the "Alleluia" in Lent; of depicting Christ as a lamb; and the discipline of celibacy for all bishops, priests and deacons. This last merits further elaboration: the Council did not merely condemn the discipline of celibacy in the case of priests and deacons, but also declared that anyone who tries to separate a priest or deacon from his wife is to be excommunicated. Likewise any cleric who leaves his wife because he is ordained is also to be excommunicated.