This period has been esteemedby many to be of the highest importance in chro nology, as affording a common standard for the adjustment of different epochs. Modern chronologers are not however so warm in their admiration of it as their predecessors have been. A common standard is unquestionably of the highest consequence in the comparison of dates and xras, and in the general arrangement and division of time ; and from its great utility, and the necessity of its frequent application, it is of importance that it should be as simple as possible in its na ture and construction. The Julian period is liable to objection on the latter score, as being rather complicated in its forma tion ; and its necessity is now altogether superseded by the very general adoption of the Christian xra as the standard of time. Any events or xras, prior or sub sequent to its commencement, may easily be computed by it, and the date of them be impressed in the memory with very little exertion or difficulty.
It remains that we give some account of Epochs and vEras, terms which con stantly recur in history, and the elucida tion of which belongs to the province of chronology. An epoch is a certain point, generally determined by some remarka ble event, from which time is reckoned: and the years computed from that period are denominated an xra. The birth of Christ is considered as an epoch—the years reckoned from that event are called the Christian xra.
In sacred chronology, the first and most remarkable epoch is that of the creation of the world. As learned men could not agree as to the precise time when this took place, the folly of reckoning from it as a standard soon became appearent, and the practice was in consequence aban doned. Archbishop Usher, whose scrip ture chronology is adopted in our Eng lish Bibles, fixes this event in the year 4004 before Christ. Play fair places it in 4007.
The universal deluge forms another epoch, this is placed by Usher in the year B. C. 2349. A third sacred epoch is the call of .Ab raham, which happened, accord ing to the same learned authority, B. C. 1921. The next epoch is the departure of the Israelites from Egypt, which Usher places B. C. 1491.
In profane history, we shall first notice the epoch of the Argonautic expedition, an event much celebrated in ancient his tory, and of some importance in chrono logical discussion, from being adopted by Sir Issac Newton as the foundation of his system of chronology. The date of this transaction has been placed in the year 1225 B. C. but in this chronologers are
not agreed.
The destruction of Troy ffirms another remarkable epoch. Considerable uncer tai ntly prevails as to the exact time when this event, as well as the preceding, took place. Playfair fixes it in the year B. C, 1184.
The xra of the Olympiads we have no ticed above, and it will be unnecessary to give any farther account of it here. The epoch of the building of Rome is the next that claims our attention. From the total want of early records, and other necessa ry documents for deciding the question, the date of this event is involved in the obscurity common to many other remote occurrences. The Roman writers them selves, and all who have followed them on the subject, differ widely respecting it. Polybius fixes it in the year B. C. 751. Cato, and others, one year earlier. Terentius Varro places it in 753 B. C. Fabius Pictor, who is followet! by Diodo rus Siculus, assigns it to 747 B. C. Sir Isaac Newton adopts the year 627 B. C. and Playfair, after Varro, whose computa tion was used by the Roman Emperors in their public instruments, places it in the year B. C. 753. Great use is made of this epoch in the histories of ancient Rome, and the historical student will do well to ascertain, if possible, what opi nion the author he may be perusing adopts, and to what year of the Christian xra the first year of Rome, according to his author, corresponds. The dates of the events will by this method be accu rately ascertained as he proceeds. The Romans sometimes reckoned the year from the establishment of the consular dignity, and afterwards from the years of the Emperors.
The xra of Nabonassar is another of those standards by which the dates of events in some histories are regulated. Nabonassar was the founder of the Ba bylonish monarchy. This zra is reckoned from the commencement of his reign, which is placed in the year B. C. 747, of the Julian period 3967, and extends as far down as the death of Alexander. The Nabonassarean year consists of 12 months of 30 days each, and five intercalary days, making in all 365 days.
The xra of the Seleucidx, or, as it is sometimes called, the year of the con tracts, is reckoned from the establish ment of Seleucus, one of Alexander's generals, after that conqueror's death, in the empire of Babylon, and is reckoned from the year B. C. 312. It is generally supposed to have begun in the spring. It was used in a large district cf Asia, and adopted by the Jews.