Epoch. 1. The point of time, usually marked hy some important event, from which a series of _years, termed an (era, is computed or dated ; although "epoch" and "sera" are often used synonymouslj' for either a chronological period or date in general (see Penny Cyclopmdia, s. v. ^ra). An a;ra properly so called the ancient Hebrews did not possess. Signal events seem to have been made use of as points from w^hich to date. Moses, like Herodotus, reckoned by generations. The Exodus, as may be seen in Exod. xix, 1, and Num. xxxiii, 3S, probably, also, the build- ing of the first Temple (1 Kings ix, 10; 2 Chron. iii, 2), were emploj'ed as starting-points to aid in assign- ing events their position in historical succession. Also the destruction of the first Temple, or the beginning of the Babylonish captivity (in the summer of the year B.C. 586), and the liberation of the Jews from the Syr- ian yoke 1)}' the valor of the Maccabees (in the autumn of the year B.C. 143), were used as epochs from which time was reckoned. After the manner of other na- tions, the Hebrews computed time by the succession of tlieir princes, as may be seen throughout the books of Kings and Chronicles. At a later period, and in the first book of the Maccabees, what is termed the Greek a3ra, or that of the Selcucidse, began to be em- ployed. Tliis a;ra, which is also called the a;ra of the Sja-o-Macedonians, commences from the year of Rome 442, twelve years after the death of Alexander, and 311 j'ears and four months l)eforc the birth of our Sav- iour, the epoch of the first conquest of Selcucus Nica- tor in that part of the West whicli afterwards com- posed the immense empire of Syria (see Noris, Annus et epoch I iSyro-Macedonum, Lips. 1606). The Julian year, formed of the Roman months, to which Syrian names were given, was used. The asra prevailed not onl}' in the dominions of Seleucus, but among almost all the people of the Levant, where it still exists. The Jews did not abandon the use of this sera, until within
the last 400 years. At present thej' date from the Creation, which they hold to have taken place 3760 years and three months before the commencement of the Christian a?ra. In order to fix their new moons and years, as well as their feasts and festivals, they were obliged to make use of astronomical calculations and cj'cles. The first cycle the}^ used for this purpose was one of 84 years, but this being discovered to be faulty, they had recourse to the Metonic cj-cle of 19 years, which was established by the authority of rab- bi Hillel, prince of the Sanliedrim, about the year 360 of the Christian a;ra. This they still use, and say it is to be observed till the coming of the Messiah. In- deed, some contend that their present practice of dat- ing from the Creation of the world is of great antiquity. Their year is luni-solar, consisting either of 12 or 13 months each, and each month of 29 or 30 days ; for in the compass of the INIetonic cycle there are 12 common years, consisting of 12 months, and seven intercalary j-ears, consisting of 13 months, which are the third, sixth, eighth, eleventh, fourteenth, seventeenth, and nineteenth of the cycle. See Chkoxology.
The birth of the Saviour of the world probably took place somewhat earlier than the date which is usually assigned to it. Usage, however, has long fixed the sera to which it gave rise, nameh', the Christian cera, or the tera of the Incarnation, to begin on the 10th day of January, in the middle of the fourth year of the 194th Olj'mpiad, the 753d year of the building of Rome, and in the 4714th of the Julian period. The use of the Christian ajra was introduced in the sixth century ; in France it was first employed in the sev- enth. About the eighth it was generally adopted; but considerable difference has existed not only in va- rious countries, but even in the same place in the same country and at the same period, respecting the com- mencement of the year. Nor did the use of the sra become universal in Christendom till the fifteenth cen- turj'. The Christian year consists of 365 days for three successive years, and of 366 in the fourth, which is termed leap-year. This computation subsisted for 1000 years without alteration, and is still used by the Greek Church. The simplicity of this form has brought it into verj' general use, and it is customary for astron- omers and chronologists, in treating of ancient times, to date back in the same order from its commence- ment. There is, unfortunately, a little ambiguity on this head, some persons reckoning the year immedi- ately before the birth of Christ as 1 B.C., and others noting it with 0, and the second year before Christ with 1, thus producing one year less than those who use the former notation. The first, however, is the usual mode. The Christian year, arranged as has been shown, was 11' 11" too long, an error which amounted to a day in nearly 129 years. Towards the end of tlie sixteenth century the time of celebrating the Church festivals had advanced ten days beyond the periods fixed by the Council of Nice in 325. It was, in consequence, ordered by a bull of Gregory XIII that the year 1582 should consist of only 355 days, which was brought about by omitting ten days in the month of October, namely, from the 5th to the 14th. And to prevent the recurrence of a like iiTeg- ularity, it was also ordered that in three centuries out of four the last year should be a common instead of a leap-year, as it would have been by the Julian Calen- dar. The year 1600 remained a leap-year, but 1700, 1800, and 1900 were to be common years. This amended mode of computing was called " The New Stylo." It was immediately adopted in all Catholic, countries, but Protestants came to use it only gradu- ally. In England the reformed calendar was adopted in the year 1752 by omitting eleven days, to which the difference betwson the styles then amounted. The alteration was effected in the month of September, the day which would have been the third being called the fourteenth. See Vulgar ^Era.