The Saros of the Chaldaeans, the Olympiad of the Greeks, and the Roman **Indiction** are instances of this mode of reckoning time.

The cycle of **Indiction** was very generally followed in the Roman empire for some centuries before the adoption of the Christian era.

The Constantinopolitan **Indiction**, like the Greek year, commenced with the month of September.

The Imperial or Constantinian **Indiction** is so called because its establishment is attributed to Constantine.

The Roman or Pontifical **Indiction** began on the 25th of December or 1st of January, according as the Christian year was held to begin on the one or other of these days.

Besides the solar and lunar cycles, there is a third of 15 years, called the cycle of **indiction**, frequently employed in the computations of chronologists.

The Julian period, proposed by the celebrated Joseph Scaliger as an universal measure of chronology, is formed by taking the continued product of the three cycles of the sun, of the moon, and of the **indiction**,and is consequently 28 X 19X I 5= 7980 years.

We have already seen that the year 1 of the era had Io for its number in the solar cycle, 2 in the lunar cycle, and 4 in the cycle of **indiction**; the question is therefore to find a number such, that Iv.