Mathematical Garden

On the Roman or common year, and its various beginnings. Chapter 3.

The Roman year (which began from Julius Caesar, in the forty-fifth year before the birth of Christ) is either common or bissextile. The simply common year consists (as I said above) of 365 days, more or less. The bissextile, however, of 366, because one day is added to it. Furthermore, the year, whatever it may be, has different beginnings according to the various nations of the world. For Numa Pompilius began his year from the Winter Solstice, because at that time the Sun begins to ascend toward us. Whence Ovid:

The first of the new year is the winter solstice, the last of the old Sun.
Phoebus and the year take the same beginning.

However, according to the Jews, Egyptians, Persians, Greeks, and all oriental nations, the year begins from the Autumn Equinox, namely from the conjunction of the luminaries nearest to it, whether it is celebrated before or after. Among the Arabs, the beginning of the year is celebrated in mid-Summer, when the Sun is in Leo. Among the Alexandrians, it has its beginning on the fourth day before the calends of September, that is, the 29th of August (as Paul, Bishop of Fossombrone, reports).

Nativity of Rome.

Among the Romans, however, on the calends of January; although more particularly in Rome they begin the year in the month of April, when Rome was founded, which they say was in mid-Spring, namely on the 20th of April, at the 22nd hour, 50th minute of the Italian clock, near the end of the sixth Olympiad, as Giovanni Lucidus opines.

Origin of the world.

Among the Hebrews, however, the year has its beginning from the conjunction nearest to the vernal equinox. Whence it is clear that for them, there is a double beginning of the year. Similarly, according to theology, the year is worthily seen to be begun from March, since the world was created on the fifteenth day before the calends of April, on a Sunday, with the Sun entering the beginning of Aries. Likewise, by the command of the Lord in the twelfth chapter of Exodus regarding March, saying: This month will be the first in the months of the year. Whence the verses:

When all things bloom, then is the new age of time.
Thus the year will have to be begun through the Spring.

The same beginning also exists among astronomers, namely when the Sun first enters the beginning of Aries: because then the world (as I said) was created. Hence astrologers, as if from the revolution of its own birth, expect the fortune imminent for each year. How this kind of beginning is discovered exactly for each year, we will clarify below in chapters 59, 60, and 61 of the fifth treatise.