The Latin verb “indīcere, indīxī, indictus” (not to be confused with “indĭcāre”), originally meant “to declare publicly, proclaim, announce, to appoint”, and more broadly, “to impose, or inflict”, especially a penalty. From it is derived the noun “indictio”, meaning “the imposition of a tax.” This was originally used most often used to mean the regular reassessment of land taxes, which originally took place on a fifteen-year cycle, first attested in 42 AD. It could also refer to the compulsory purchase of food, clothing and other goods for the use of the army and the courts. (Oxford Classical Dict. ad vocem)
Towards the end of the 4th century, the emperor Diocletian imposed a far-reaching program of financial reform on the Roman Empire. As part of this, “indictio” was used as the general term for the annual assessment of all levies in kind. The date at which such assessments began was September 1st, approximately the end of the harvest season for many crops in the Mediterranean regions, and so an appropriate time to calculate the taxes to be paid on them.
During the reign of Constantine, starting in 312 A.D., “indictio” first appeared in official documents as part of a dating system; so e.g., the period which we call “Sept. 1, 312 to Aug. 31, 313” would be known as “the first year of the indiction”, “Sept. 1, 313 to Aug. 31, 314” as “the second year”, etc. By the middle of the 4th century, this system began to appear on documents unrelated to taxation, and in 537, the emperor Justinian declared that all official documents must include the year of the indiction, a usage which continued throughout the Middle Ages in both East and West. As a technical term, it passed into Greek as either ἰνδικτιών or ἴνδικτος (fem.), and it still used to this day. Over time, September 1st came to be recognized as the official beginning of the civil New Year; it continued as such in the Byzantine Empire until the fall of Constantinople in 1453, and in Russia until 1699, when it was changed to Jan. 1 by Tsar Peter I as part of his program of Westernizing reforms.
(An inscription of the year 1238 in the portico of the church of St Eusebius on the Esquiline Hill in Rome, which in the very first line, refers to the “eleventh indiction”, i.e. the eleventh year of the cycle. Image from Wikimedia Commons by Sailko, CC BY-SA 3.0)
This gave rise to the custom by which the Byzantine Rite celebrates the day as the formal beginning of its liturgical year, with the title “Ἀρχὴ τῆς Ἰνδίκτου, ἤτοι τοῦ νέου Ἔτους – the beginning of the indiction, that is, of the New Year.”
In the Byzantine tradition, the creation of the world is also considered to have taken place on the Indiction, a fact to which the liturgical texts of the day refer repeatedly. For example, at the Divine Liturgy, the following texts are sung:
“Maker of all creation, Who settest times and seasons in Thy power, bless the crown of the year of Thy goodness, o Lord, keeping in peace Thy kings and Thy city, by the prayers of the Mother of God, and save us.
Maker and Master of the ages, God of all things, and truly greater than all, bless this year, saving in Thy boundless mercy, o Compassionate One, all that serve Thee, the only Master, and cry out in reverence: o Redeemer, grant a bountiful year to all.”
Many early Christians attempted to calculate the age of the world, as the Jews had before them, working from the relevant statements of the Bible, and, not surprisingly, coming up with varying results. According to the reckoning most commonly accepted in the Byzantine world, the creation began in 5509 B.C, making this Annus Mundi 7531. This reckoning is still used by some Orthodox Christians in conjunction with the western ‘Anno Domini’ system for things like ecclesiastical calendars and the inscription of dates on the cornerstone of a church.
(The Creation of the World; 12th century Byzantine mosaic in the cathedral of Monreale, Sicily. Public domain image from Wikimedia Commons.)