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: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 of his right to make this claim. In fact, 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 an acceptance that could be summed up as expressed by Pope John VIII: that he accepted all those canons which did not contradict the true faith, good morals, and decrees of Rome. The Orthodox Churches consider this council as ecumenical and adds its canons to the decrees of the Fifth and Sixth Councils, although their authority has been more often theoretical than real.
Many of the canons were reiterations of previously passed canons. However, most of the new canons exhibited an inimical attitude towards churches not in disciplinary accord with Constantinople, especially the Western Churches. Their customs are anathematized and "every little detail of difference is remembered to be condemned" (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: not content merely to condemn the discipline of celibacy in the case of priests and deacons, the Council 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.