TheCommunion (Latin:communio;Ancient Greek:κοινωνικόν,koinonikon) is a refrain sung with psalm recitation during the distribution of theEucharist in theDivine Liturgy orMass. As chant it was connected with the ritual act ofChristian communion.
According to Dimitri Conomos thekoinonikon (κοινωνικόν), as it is sung as an elaborated communion chant during theDivine Liturgy, has derived from an early practice of psalm recitation similar to Western liturgies, when theKoinonikon served as atroparion.[1] The oldesttroparion which was used for communion, was "Γεύσασθε καὶ ἴδετε" ("O taste and see that the Lord is good", Ps. 33:9). It was supposed to symbolize the last supper celebrated onMaundy Thursday. During the 5th century, when the DivineLiturgy of the Presanctified Gifts had established and this communion chant became associated with it, the custom spread over the Lenten period, presumably with the recitation of different psalm sections (staseis).
In the earlyAsmatika (12th and 13th century), the choirbook of the cathedral rite, this koinonikon is classified asechos protos (transcribed asa—α′) according to the modal signatures of theOctoechos, but its archaic melos does not finish on thefinalis andbasis of this echos, but with the one (phthongos) ofechos plagios devteros (transcribed asE—πλβ′).[2]
In the cathedral rite of Constantinople thekoinonikon as atroparion became so elaborated, that it was sung without psalm recitation.

Nevertheless, its text was usually astichos taken from the psalter, like the SundayKoinonikon of the Week Cycle Αἰνεῖτε τὸν κύριον ("Praise the Lord" Ps 148:1), which had already added as anOctoechos cycle in 13th-century GreekAsmatika, so that they could be performed according to theechos of the week.[3] Within the weekly cycle each koinonikon was also specified to certain liturgical occasions such as the Wednesdaykoinonikon Ποτήριον σωτηρίου ("Cup of salvation" Ps 115:4) which was dedicated to feasts around the Theotokos or around martyres. Apart from the week cycle there was a repertory of 26koinonika which developed as a calendaric cycle of immoveable and moveable feasts during the 9th century and they can be found in the books of the cathedral rite since the 12th century (psaltikon andasmatikon).[4]
Since the 14th century, when a mixed rite had replaced the former tradition of the cathedral rite atHagia Sophia, the old models have been elaborated in compositions of the Maistores like John Glykys,John Koukouzeles, andManuel Chrysaphes.
The communion part of theAmbrosian Mass, as it had been celebrated in the cathedrals of Milan (called after the famous local bishopAmbrose), was composed around theAnaphora. It was opened by a litany called "Ter Kyrie", thePater Noster, and the chant which preceded thePostcommunio, was called "Transitorium".
According toIsidore of Seville (Etymologiae, De ecclesiasticis officiis) and Pseudo-Germanus'Expositio Antiquae Liturgiae Gallicanae[5] the communion chant of the Mass in theGallican rite of France and theVisigothic rite of Spain was calledConfractorium and probably connected with a ritual breaking (fraction) ofsacramental bread.
According to James McKinnon thecommunio became late part ofRoman Mass, and like in many other Western sources, there is no early evidence of a Latin equivalent of the Ps. 33:9 ("Gustate et videte") as a kind of prototype of the genre, butOrdo romanus I describes the communion chant as an antiphon with psalm sung by theSchola cantorum accompanying the distribution of the Eucharist, until the presiding pope interrupts it.[6] Nevertheless, the genrecommunio became an important and favored subject in the process of a compositional planning of the Mass Proper by the leader of theSchola cantorum, which had already about 141 items during the 7th century. The dramaturgy in the composition of communion chants and the choice of scriptural texts from Advent to Epiphany includes the composition of an epic recitation of prophetic texts before Christmas, while the later serial of communion chants use extracts from the gospel readings of the day, composed in a rather dramatic style.[7]
Since the Carolingian reform the Roman Mass Proper became part of theRoman-Frankish liturgy and the most common musical settings of it were reserved for special Masses such asRequiem Masses, where the chant has theincipitLux aeterna.
Incontemporary Catholic usage, the communion chant corresponds to theCommunion Antiphon and is sung or recited audibly throughout by the faithful.