September 1 begins the Eastern Orthodox calendar year, and this one happens to be the first in another Indiction cycle. Following is the information on the Indiction from The Great Horologion (translated and published by Holy Transfiguration Monastery) entries for September 1. Mind you, this is from one of our service books:
Beginning of the Indiction: For the maintenance of their armed forces, the Roman emperors decreed that their subjects in every district should be taxed every year. This same decree was reissued every fifteen years, since the Roman soldiers were obliged to serve for fifteen years. At the end of each fifteen-year period, an assessment was made of what economic changes had taken place, and a new tax was decreed, which was to be paid over the span of the fifteen years. This imperial tax decree, which was issued before the season of winter, was named Indictio, that is, Definition, or Order. This name was adopted by the emperors in Constantinople also. At other times, the latter also used the term Epinemisis, that is, Distribution (Dianome). It is commonly held that Saint Constantine the Great introduced the Indiction decrees in A.D. 312, after he beheld the sign of the Cross in heaven and vanquished Maxentius and was proclaimed Emperor in the West. Some, however (and this seems more likely), ascribe the institution of the Indiction to Augustus Caesar, three years before the birth of Christ. Those who hold this view offer as proof the papal bull issued in A.D. 781 which is dated thus: Anno IV, Indictionis LIII — that is, the fourth year of the fifty-third Indiction. From this, we can deduce the aforementioned year (3 B.C.) by multiplying the fifty-two complete Indictions by the number of years in each (15), and adding the three years of the fifty-third Indiction. There are three types of Indictions: 1) That which was introduced in the West, and which is called Imperial; 2.) The so-called Papal Indiction, which begins on the 1st of January; and 3) The Constantinopolitan, which was adopted by the Patriarchs of that city after the fall of the Eastern Empire in 1453. This Indiction is indicated in their own hand on the decrees they issue, without the numeration of the fifteen years. This Indiction begins on the 1st of September and is observed with special ceremony in the Church. Since the completion of each year takes place, as it were, with the harvest and gathering of the crops into storehouses, and we begin anew from henceforth the sowing of seed in the earth for the production of future crops, September is considered the beginning of the New Year. The Church also keeps festival this day, beseeching God for fair weather, seasonable rains, and the abundance of the fruits of the earth. The Holy Scriptures (Lev. 23:24-5 AND Num. 29:1-2) also testify that the people of Israel celbrated the feast of the Blowing of the Trumpets on this day, offering hymns of thanksgiving. In addition to all the aforesaid, on this feast we also commemorate our Saviour’s entry into the synagogue in Nazareth, where He was given the book of the Prophet Esaias to read, and He opened it and found the place where it is written, “The Spirit of the Lord is upon Me, for which cause He hath anointed Me . . . ” (Luke 4:16-30).
It should be noted that to the present day, the Church has always celebrated the beginning of the New Year on September 1. This was the custom in Constantinople until its fall in 1453 and in Russia until the reign of Peter I. September 1 is still festively celebrated as the New Year at the Patriarchate in Constantinople; among the Jews also the New Year, although reckoned according to a moveable calendar, usually falls in September. The service of the Menaion for January 1 is for our Lord’s Circumcision and for the memorial of Saint Basil the Great, without any mention of its being the beginning of a new year.
Dismissal Hymn of the Indiction, Second Tone
O Maker of all creation, Who hast established the times and the seasons in Thine own power: Bless the crown of this year with Thy goodness, O Lord, and keep our rulers and Thy flock in peace, by the intercessions of the Theotokos, and save us.
Kontakion of the Indiction. Fourth Tone.
Thou Who wast raised up
O God of all, Thou Who hast made all the ages
O Sovereign Lord, truly transcendent in essence,
bestow Thy grace and blessing on the year to come;
and, O Most Compassionate,
in Thine infinite mercy
save all them that worship Thee,
Who alone art our Master,
and that with fear, O Saviour, cry to Thee:
Grant unto all men a fruitful and godly year.