Era of Nabonassar
This era is famous in astronomy, having been generally
followed by Hipparchus and Ptolemy. It is believed to
have been in use from the very time of its origin; for the
observations of eclipses which were collected in Chaldea
by Callisthenes, the general of Alexander, and transmitted
by him to Aristotle, were for the greater part referred to
the commencement of the reign of Nabonassar, founder of
the kingdom of the Babylonians. It is the basis of the
famous Canon of Kings, also called Mathematical Canon,
preserved to us in the works of Ptolemy, which, before
the recent astonishing discoveries at Nineveh, was the sole
authentic monument of Assyrian and Babylonian history
known to us. The epoch from which it is reckoned is
precisely determined by numerous celestial phenomena
recorded by Ptolemy, and corresponds to Wednesday at
mid-day, the 26th of February of the year 747 before
Christ. The year was in all respects the same as the
ancient Egyptian year. On account of the difference in
the length of the Julian and Babylonian years, the conversion of dates according to the era of Nabonassar into
years before Christ is attended with considerable trouble.
The surest way is to follow a comparative table. Frequently the year cannot be fixed with certainty, unless we
know also the month and the day.
The Greeks of Alexandria formerly employed the era of
Nabonassar, with a year of 365 days; but soon after the
reformation of the calendar by Julius Cæsar, they adopted,
like other Roman provincials, the Julian intercalation.
At this time the first of Thoth had receded to the 29th of
August. In the year 136 of our era, the first of Thoth
in the ancient Egyptian year corresponded with the 20th
of July, between which and the 29th of August there are
forty days. The adoption of the Julian year must therefore
have taken place about 160 years before the year 136 of
our era (the difference between the Egyptian and Julian
years being one day in four years), that is to say, about the
year 25 B.C. In fact, the first of Thoth corresponded with
the 29th of August in the Julian calendar, in the years 25, 24, 23, and 22 B.C.
Era of the Seleucidæ, or Macedonian Era.
The era of the Seleucidæ dates from the time of the
occupation of Babylon by Seleucus Nicator, 311 years
before Christ, in the year of Rome 442, and twelve years
after the death of Alexander the Great. It was adopted
not only in the monarchy of the Seleucidæ but in general
in all the Greek countries bordering on the Levant, was
followed by the Jews till the 15th century, and is said to
be used by some Arabians even at the present day. By
the Jews it was called the Era of Contracts, because the
Syrian governors compelled them to make use of it in civil
contracts; the writers of the books of Maccabees call it the
Era of Kings. But notwithstanding its general prevalence
in the East for many centuries, authors using it differ much
with regard to their manner of expressing dates, in consequence of the different epochs adopted for the commencement of the year. Among the Syrian Greeks the year
began with the mouth Elul, which corresponds to our
September. The Nestorians and Jacobites at the present
day suppose it to begin with the following month, or
October. The author of the first book of Maccabees
makes the era commence with the month Nisan, or April;
and the author of the second book with the first Tishrin, or October. Albategni, a celebrated Arabian astronomer,
dates from the 1st of October. Some of the Arabian
writers, as Alfergani, date from the 1st of September.
At Tyre the year was counted from the 19th of our
October, at Gaza from the 28th of the same month, and at
Damascus from the vernal equinox. These discrepancies
render it extremely difficult to determine the exact correspondence of Macedonian dates with those of other eras;
and the difficulty is rendered still greater by the want of
uniformity in respect of the length of the year. Some
authors who follow the Macedonian era, use the Egyptian
or vague year of 365 days; Albategni adopts the Julian
year of 36514 days.
According to the computation most generally followed,
the year 312 of the era of the Seleucidæ began on the 1st
of September in the Julian year preceding the first of our
era. Hence, to reduce a Macedonian date to the common
era, subtract 311 years and four months.
The names of the Syrian and Macedonian months, and
their correspondence with the Roman months, are as
follows:—
| Syrian. | Macedonian. | English. | ||
| Elul. | Gorpiæus. | September. | ||
| Tishrin I. | Hyperberetæus. | October. | ||
| Tishrin II. | Dius. | November. | ||
| Canun I. | Apellæus. | December. | ||
| Canun II. | Audynæus. | January. | ||
| Sabat. | Peritius. | February. | ||
| Adar. | Dystrus. | March. | ||
| Nisan. | Xanthicus. | April. | ||
| Ayar. | Artemisius. | May. | ||
| Haziran. | Dæsius. | June. | ||
| Tamus. | Panemus. | July. | ||
| Ab. | Loüs. | August. |
Era of Alexander.
Some of the Greek historians have assumed as a chronological epoch the death of Alexander the Great, which
took place in the year 325 B.C. The form of the year is
the same as in the preceding era. This era has not been
much followed; but it requires to be noticed in order
that it may not be confounded with the era of the Seleucidæ.
Era of Tyre.
The era of Tyre is reckoned from the 19th of October, or
the beginning of the Macedonian month Hyperberetæus,
in the year 126 B.C. In order, therefore, to reduce it to
the common era, subtract 125; and when the date is B.C.,
subtract it from 126. Dates expressed according to this era
occur only on a few medals, and in the acts of certain
councils.
Cæsarean Era of Antioch.
This era was established to commemorate the victory
obtained by Julius Cæsar on the plains of Pharsalia, on
the 9th of August in the year 48 B.C., and the 706th of
Rome. The Syrians computed it from their month Tishrin I.; but the Greeks threw it back to the month Gorpiæus
of the preceding year. Hence there is a difference of eleven
months between the epochs assumed by the Syrians and
the Greeks. According to the computation of the Greeks,
the year of the Cæsarean era began in the autumn of
the year preceding the commencement of the Christian era;
and, according to the Syrians, the 49th year began in the
autumn of the first year of the Incarnation. It is followed
by Evagrius in his Ecclesiastical History.
Julian Era.
The Julian era commences with the 1st of January,
forty-five years B.C. It was designed to commemorate the
reformation of the Roman calendar by Julius Cæsar.
Era of Spain, or of the Cæsars.
