Fourth Council of Dvin

The Fourth Council of Dvin was a Church Council held in Dvin the ancient capital city of Armenia in 648. The council was presided over by Catholicos Nerses III of Ishkhantsi (641-661) and was attended by 17 participating bishops.

Overview
The council was called by the Armenian Crown and chief Bishops to address the ongoing schism between the Armenian Apostolic Church, and the western Orthodox and Catholic churches. Of particular concern was the recent schism with the Georgian Church, which had originally sided with Armenia in rejecting the Chalcedon canons but has recently changed sides by supporting Rome and Constantinople. A strong case of unification with Georgia was pursued at the council but was ultimately rejected. The council also adopted 12 canons, and strengthened church discipline.

The singing of Armenian Church hymns was also discussed. These were modified by vardapet Barsegh Jon and approved by Catholicos  Nerses III. The system is now known as Jonundir, meaning "arranged by Barsegh Jon.".

Other Dvin councils
Some parts of the Armenian church recognize two more councils. In particular, they see the Fourth Council as occurring in 645, with the meeting in 648 being the Fifth Council (both presided over by Nerses III).

A Sixth Council is said to have been held in 719 during the Pontificate of Hovhannes III. The Paulicians and Docetisms were discussed and 32 canons were established, including some on the blessing of marriage and holy objects.