In the traditional Mass lectionary of the Roman Rite, the Gospel for today is St John 10, 22-38, which begins as follows: “In illo tempore: Facta sunt Encaenia in Jerosolymis, et hiems erat. Et ambulabat Jesus in templo, in porticu Salomonis. – At that time: it was the feast of the dedication at Jerusalem, and it was winter, and Jesus walked in the temple, in Solomon’s porch.”
In the Divine Office, a commentary on this is read from St Augustine’s Treatises on the Gospel of St John, in which he says, “The festival called ‘Encaenia (ἐγκαίνια)’ was the dedication of the temple. For in Greek, the word ‘caenon (καινόν)’ means ‘new.’ Whenever any new thing is dedicated, this is called ‘encaenia.’ This word now has a common use: if someone puts on a new coat, he is said to ‘encaeniare.’ For the Jews solemnly celebrated that day on which the temple was dedicated; this feast day was being observed when the Lord spoke the words which have been read.” This makes for an interesting testimony to the way the common speech of the Latin world absorbed words from Greek.
From the very beginning, Christian Latin retained a number of Greek words as technical terms, which in some cases served to distinguish them from their pagan counterparts. A Christian church had a “diaconus”, not a “servus” or “famulus”, was led by a “presbyter”, not (at first) by a “sacerdos”, and the local community of churches was ruled by an “episcopus.” These words are still in common use today in English, as “deacon”, “priest” and “bishop.” Although it has left no trace in English, “encaenia” seems to have been regarded in the same way by the original Latin translators of the Gospels, since they left it untranslated in the passage cited above. Likewise, St Jerome, left it unaltered when he revised their work to produce the Latin version of the Gospels which we now call the Vulgate. To some degree, this may have also been because “novus – new” had a lot of negative connotations for the Romans, and the translation of “ἐγκαίνια” as “innovatio” would sound to them more like “novelty” or “innovation” rather than “renewal.”
The Jewish people called the feast of the dedication of the temple in Jerusalem by this term, derived from the word for “new”, in memory of the two occasions on which it was rebuilt: first, after the return from the Babylonian exile in the late 6th century BC., and again in the reign of King Herod I, from roughly 20-10 BC. By the time the Christians were granted freedom of worship by Emperor Constantine in 312 and began to build large public churches, the temple in Jerusalem had long since been destroyed, in the great sack of the Holy City in 70 A.D.
The word was therefore taken over as the name of the annual commemoration of the dedication of the most important church in Jerusalem, the Basilica of the Resurrection, which is today more generally called the church of the Holy Sepulcher. The various churches of the Byzantine Rite still celebrate this feast every year on September 13. The Georgian Church also took the word into its liturgy without translating it (enk‘eniay), indicating that it was also treated as a technical term better left untranslated in the East.