= [(Ol – 1) * 4 + (t – 1)] – 775,
where “Ol” is the number of the Olympic Games, and “t” is the number of the year since the Olympiad.
For example, the 4th year of the 48th Olympiad (Ol. 48.4) converts into -584 NE, or 585 BNE. This was the year of the eclipse of Thales (see Pliny the Elder. Natural History, 2,12).
The Egyptian calendar
The Roman calendar was a modification of the Egyptian calendar. A number of ancient writers (mainly from the church of Alexandria) continued to use the Egyptian calendar even after the Julian calendar was in wide use.
The Egyptian calendar consisted of 12 months, 30 days each. The Greek names of the months are as follows: 1. Thoth, 2. Phaophi, 3. Athyr, 4. Choiak, 5. Tybi, 6. Mechir, 7. Phamenoth, 8. Pharmuthi, 9. Pachon, 10. Payni, 11. Epiphi, 12. Mesori.
At the end of the year, five more days were added, which were called in Greek “epagomen”. So, there were the total of 365 days in the Egyptian calendar year.
Claudius Ptolemy (c. 100 – c. 170 NE), the ancient Greek scholar, is credited with tracing the beginnings of the Egyptian calendar down to the enthronement of the Babylonian king Nabonassar. The reference point of the Nabonassar era (1 Toth) corresponds to February 26, 747 BNE.
The exact alignment of eras
Based on the above, the following equasion can be suggested:
1 NE = 754 a.u.c. = Ol. 195.1 = 748 Nabonassar
As you may have noticed, the formulas for converting dates between different chronologies are approximate; they do not account for the differences between the times of change from one year to the next for the specified eras. Using these formulas, the calculations can sometimes be off by a whole year. To avoid it, it is necessary to take into account the exact date of an event (day and month), so you can make adjustments in the process of calculations.
The Egyptian calendar is even more challenging. At first, it doesn’t seem very complicated, because we know that January 1 of the year 1 NE corresponds to Tybi 12, 748, of the Nabonassar era. However, the Egyptian year consists of 365 days, whereas the Julian calendar year is 365.25 days. That is why every 4 years these two calendars get adjusted against each other by one day. The process of converting Egyptian calendar dates into the corresponding Julian calendar dates will be explained in later chapters.
Since the foundation of the world
In the first ages of Christianity, attempts were made to count years since the foundation of the world, or from Adam. Annalists made their calculations based on the Old Testament data but came up with varying results, for which reason this type of chronology was not widely accepted. Partcularly, the scholars disagreed on how much time had passed from the Babylonean exile of the Jews (6th century BNE) up to the New Testament events, because the Bible does not cover this chronological period. So they had to use external chronicles, which were not always reliable. Only several versions of the eras “since the foundation of the world” have any historical significance:
The Antioch era (reference point: September 1, 5500 BNE, Friday). Developed by the bishop Theophilus of Antioch, circa 180. Some sources give other reference points: 5969, 5515, or 5507 BNE. But they were not used in the chronicles.
The era of Hippolytus of Rome (reference point: 5503 BNE). Appeared around the year 200.
The era of Sextus Julius Africanus (reference point 5502 BNE). Appeared around 220; used in “Chronography”.
Theophilus, Hippolytus, Julius and other ancient writers believed that the period of time between Adam and the New Testament (Jesus Christ) was 5500 years. The basis for this belief was the biblical account of the creation of man in the middle of the 6th day (Gen 1:24—31), and also the words of Scripture: “For a thousand years in thy sight are but as yesterday when it is past” (Ps 90:4 [Ps 89:5 rus]), and: “But, beloved, be not ignorant of this one thing, that one day is with the Lord as a thousand years, and a thousand years as one day” (2 Pet 3:8). There were often discrepancies in these eras as to the date of Christ’s birth. Some scholars believed that 5500 years was an approximate marker – the Bible does not conclusively say that Adam was created exactly in the middle of the 6th day. So deviations from this date were allowed. There were also some who counted 5500 years from Adam’s fall, not from the foundation of the world. Other denied any correlation between the millenia on the timeline of history and the number of creation days.
The Old Byzantine era (reference point: 5504 BNE). Used in Byzantium until the 4th century. Also used in the ancient Rus and Bulgaria.
The Byzantine era (reference point: September 1, 5509 BNE, Saturday). Introduced under the Emperor Constantius in the 4th century. It was used in Byzantinum up to the 6th century, and in Russia starting with 15th century. The reference point was shifted so that the indiction numbers would be easier to find. For the year 5509 BNE, the indiction numbers equal one. For the succeeding years, the indiction numbers are the remainder of the division of the Byzantine date by 28, 19, and 15. The remainder value equalled to the circle of the Sun, the Moon and the indiction, respectively.
The era of Panodorus of Alexandria (reference point August 29, 5493 BNE, Tuesday). Introduced by Panodorus of Alexandria around the year 400.
The era of Annianus (reference point: March 25, 5492 BNE, Sunday). introduced by Annianus of Alexandria in the beginning of the 5th century.
The era of Alexandria (reference point: September 1, 5493 BNE, Friday). It is a modification of the eras of Panodorus and Annianus. Used by the Byzantine historians.
The March Byzantine era (reference point: March 1, 5508 BNE, Friday). Used in Byzantium starting with the 6th century, and in the ancient Rus up until the 12th century.
The Ultramarch Byzantine era (reference point: March 1, 5509 BNE, Thursday). Used in the medieval Rus, between the 12th and 15th centuries.
The eras “since the foundation of the world” were so numerous that annalists often gave their dates in several chronological systems – to avoid confusion.
The Jewish calendar
We know very little about the original Jewish calendar. Four months of the ancient calendar are mentioned in the Old Testament: Aviv [Abib] (the first month, the month of ears of corn) [Ex 13:4], Zif (the second month, month of blossoms) [1 Kings 6:1], Ethanim (the seventh month, the month of strong winds) [1 Kings 8:2], Bul (the eighth month, the month of the harvest) [1 Kings 6:38].
While in Babylonean captivity, the Jews adopted the lunisolar calendar of their captors. It is easy to verify by comparing the names of the ancient Babylon months with the contemporary Jewish calendar.
The names of the ancient Babylon months: 1. Nisannu, 2. Ayyaru, 3. Simanu, 4. Duuzu, 5. Abu, 6. Ululu, 7. Tasritu, 8. Arahsamna, 9. Kislimu, 10. Tebetu, 11. Sabatu, 12. Addaru.
The names of months in the late Jewish calendar: 1. Nisan (former Aviv), 2. Iyyar (former Zif), 3. Siwan, 4. Tammuz, 5. Ab, 6. Elul, 7. Tisri (former Ethanim), 8. Marheswan (former Bul), 9. Kislew, 10. Tebet, 11. Sebat, 12. Adar.
In the ancient Jewish world, the appearance of the first crescent in the
