e was ended.
Traces of this quindecennial period may be found in the third century,
but the formal adoption of the Indiction is generally assigned to the
Emperor Constantine, and to the year 312[187]. The Indiction itself,
and every one of the years composing it, began on the 1st of September
of the calendar year. The reason for this period being chosen probably
was that the harvests of the year being then gathered in, the
collection of the tithes of the produce, which formed an important
part of the Imperial revenue, could be at once proceeded with. What
gives an especial importance to this method of dating by Indictions,
for the reader of the following letters is, that most of the great
offices of State changed hands at the beginning of the year of the
Indiction (Sept. 1), not at the beginning of the Calendar year.

[Footnote 187: Compare Marquardt (Roemische Staatsverwaltung ii. 237).
He remarks that the Indiction seems to have been first adopted in
Egypt, and did not come into universal use all over the Empire till
the end of the Fourth Century.]

To make such a mode of dating the year at all satisfactory, it would
seem to us necessary that the number of the cycle itself, as well as
of the year in the cycle, should be given; for instance, that A.D. 313
should be called the first year of the first Indiction, and A.D. 351
the ninth year of the third Indiction. This practice, however, was not
adopted till far on into the Middle Ages[188]. At the time we are
speaking of, the word Indiction seems generally to have been given
not to the cycle itself, but to the year in the cycle. Thus, 313 was
the first Indiction, 314 the second Indiction, 315 the third
Indiction, and so on. And thus we find a year, which from other
sources we know to be 313, called the first Indiction, 351 the ninth
Indiction, 537 the fifteenth Indiction, without any clue being given
to guide us to the important point in what cycles these years held
respectively the first, the ninth, and the fifteenth places.

[Footnote 188: The Twelfth Century, according to Marquardt.]

As the Indiction began on the 1st of September a question arises
whether the calendar year is to be named after the number of the
Indiction which belongs to its beginning or its end; whether, to go
back to the beginning, A.D. 312 or A.D. 313 is to be accounted the
first Indiction. The practice of the chroniclers and of most writers
on chronology appears to be in favour of the latter