Creation Eras.— To emphasize their separa tion from paganism, and avoid participation in pagan observances connected with the calendar, the Christians early began to reckon time from the supposed date of the creation of Adam ac cording to the Jewish Scriptures. Aside from its resting only on the adding up of impossible and inconsistent genealogies, the problem was further confused by there being three texts of equal authority to work Sa maritan and Septuagint,— all irreconcilably variant. One author collects 120 different com putations of the true date; another says he has collected over 200; and 300 have been reckoned; and the estimates vary over 3,500 years, from 3,483 to 6,984 years before the Christian era. None of them have any scientific standing, but for two centuries the aristian world generally accepted as a working hypothesis Archbishop Usher's (1650) figure of 4004 a.c., which is still used in some Bible appendices and similar works. Several earlier ones, however, obtained considerable footing, and two of them are not yet disused. It is of course as useful as any other arbitrary point, like the Olympic Games or the foundation of Rome; and has the ad vantage of requiring only one continuous figure, in place of a break in the centre like the Chris tian era. But its controversial character, and the satisfaction of marking off the time after Christ's coming as the beginning of a new era, have caused the latter system to supplant it. Of the others, the chief are: (1) Era of Constanti nople, still employed in the Greek Church, and used by the Russians till the time of Peter the Great. This begins 5,508 years 4 months before the Christian era. The civil year begins 1 September; the Church year on the spring equinox or 1 April. To find the current year corresponding to a Constantinople year, if the event tonic place before 1 September, subtract 5,508 from the date; if later in the' year, sub tract 5,509: (2) Era of Alexandria. This was adopted by the Christians of Alexandria on the computation of Julius Africanus, who reckoned 5,500 years from the creation of Main to the birth of Christ, but placed the latter three years earlier than the current reckoning, so that, our era would begin 5503 Alexandrian. After the accession of Diocletian in 284, however, they drop/JO 10 years, both from the, year since the Creation and since the Incarnation, making in fact two eras instead of one. To convert this era into our own, in the first eight months of the year subtract 5,502 up to and including 5786 Alexandrian, after that date, 5,492; in the last four months, 5,503 and 5,493 respectively.
This era was used by the Coptic Church till the 15th century, and is still retained in the Abys sinian. (3) Era of Antioch. The Syrian Christians, early in the 4th century, adopted Julius Africanus' reckoning as above, but dropped 10 years from it as the Alexandrians had already done; placing the Incarnation, how ever, as in our own era, three years later than the Alexandrian. As regards the Creation, therefore, the two eras are seven years apart up to Diocletian's time, and then coincide; as regards the Incarnation, the Antioch is three years less before that time and seven years later after it. Dates in this system are reduced to ours, as in the reformed Alexandrian calen dar above.
Era of Diocletian, Subsequently Named Era of Martyrs.— At the same time that the Alexandrians changed their Creation era as above, they established a new and shorter one from the accession of Diocletian, 29 August (first of the Egyptian year) 284. The second
name given implies that an attempt was made to start it from 303, the date of Diocletian's edict of persecution, but if so it was unsuc cessful, as indeed a mere perpetuation of a strife was likely to be. The era is still used the Copts of Egypt and the Abyssinians. The change from the Egyptian to the Julian calendar, and the peculiar complications it has introduced into the conversion from that era to ours, are too intricate to detail here. To make the change, add to their date 283 years 240 days in common years; if the date is between 30 August and the end of the year in the one before leap year, add 283 years 241 days. But the Ethiopians do not reckon the years con tinuously from the beginning: at the end of each 532 years (that is, 28 X 19, or the solar and lunar cycles multiplied together) they be gin again with 1.
The Christian Era.— It is not generally re alized how modern this epoch is in general use. It was introduced into Italy 533 A.D. by Diony sius Exiguus (*the lean)), a Roman abbot; was not introduced into Gaul (France) till the 8th, and not in current use there till the 9th; and came into use in England only in the latter part of the 8th. In Latin countries the -current scheme before that was the cycle of indiction (below). Any uniform date is so useful that its defects may be overlooked. That of having a double set of numbers, forward and back, is not serious. Perhaps the chief inconvenience in calculating backward is that of calling the year preceding the era 1 'Lc. instead of 0; thereby making the leap years on the backward series fall on the odd years, 1, 5, etc., or else making 7 years between the first one previous and the first one after. Astronomers rectify this by calling the first year previous O. (For the dif ferent dates on which the beginning of the year has been placed, see CALENDAR). l)ionysius fixed the birth of Christ in 754 of the Roman era, but he began the year 1 with the Annun ciation, 25 March of the year preceding. In ecclesiastical and common usage it has begun at Christmas, Easter, 1 March, and other dates. In England from the 7th to the 13th century it was on Christmas; in the 12th the Annunciation began to be used as well, and from the 13th till 1752 remained paramount. The different be ?innings of the year must be carefully taken into account in studying mediaeval history.
Cycle of Indiction.—This was a period of 15 years, whose object has been already ex plained. It was generally used in the Western or Latin empire for several centuries before the Christion era became general. It began in the year 313, or was referred to that year as a start. There were three, differing only as to the beginning of the year: (1) The Constanti nopolitan, beginning in September, like the Greek year; generally used in the Eastern or Greek empire and sometimes in France. (2) The Imperial or Constantinian, attributed to Constantine the Great, called also the Cmsarean. It began 24 September, and was used by old French and English chroniclers. (3) The Roman or Pontifical, beginning on Christmas or 1 January as custom varied; often used in papal bulls, and sometimes in old French writers. To find the number of any year in the Indiction, add 3 to the date (our era), divide by 15, and the remainder is the number. If the remainder is 0, the year is the fifteenth or last of the cycle.