The extent of the revolving year is completed, according to the calculations of men of old who were versed in the movements of the universe and the stars, of whom the most eminent are Meton, Euctemon, Hipparchus, and Archimedes, when the sun, in accordance with the eternal law of the heavenly bodies, has traversed the signs of the heaven which in Greek are called ζωδιακός, the zodiac, and after the course of 365 days and nights returns to the same turning-point; that is (for instance) when it has started from the second degree of the Ram and after completing its course has returned to the same place.

But the true length of a year ends, in the said 365 days and six hours besides, at high noon, and the first day of the next year will extend from the end of the sixth hour to evening. The third year begins with the first watch and ends with the sixth hour of the night. The fourth goes on from midnight until broad daylight.

Therefore, in order that this computation because of the variations in the beginning of the year (since one year commences after the sixth hour of the day and another after the sixth hour of the night) may not confuse all science by a disorderly diversity, and an autumnal month may not sometimes be found to be in the spring,To effect this it was necessary to add two months to the year 46 B.C.; see Suet., 40, 2. it was decided to combine those series of six hours, which in four years amounted to twenty-four, into one day and an added night.

And after deep consideration, by the agreement of manylearned men it was arranged that the completion of the year’s course has a single definite end, and is neither changeable nor uncertain; so that the reckoning of the sun’s course no longer appears beclouded by any error, and the months retain their appointed seasons.

The Romans were long ignorant of all this, since their realm was not yet widely extended, and for many centuries they were involved in obscure difficulties; and they wandered in still deeper darkness of error when they gave over the power of intercalation to the priests, who lawlessly served the advantage of tax-collectors or of parties in litigation by arbitrarily subtracting or adding days.

From this beginning many other errors arose, which I think it superfluous to mention here. These were done away with by Octavianus AugustusActually it was Julius Caesar; cf. Suet., 40; 31, 2; though Augustus corrected a misinterpretation of Caesar’s scheme. who, following the Greeks, corrected the confusion and brought order into this inconsistency by adopting after great deliberation the arrangement of twelve months and six hours, during which the sun in its eternal course through the twelve signs completes a whole year.