Historical Dating: Jewish versus Secular
In learning through your excellent “Crash Course in Jewish History” (www.aish.com/jl/h/cc/), I notice that in referencing some historical dates, the Jewish dating system and the Christian dating system vary by as much as 150 years - but by the time we get to the Roman period (i.e. the Christian year 1) the discrepancy disappears. Why?
The Aish Rabbi Replies
The Jewish dating system is taken primarily from a book called "Seder Olam Rabba," dating back to the 2nd century CE and attributed to Rabbi Yosef ben Halafta. The sources for the dates in Halafta's book come from rabbinic traditions recorded in the Talmud as well as numerous chronologies written in the Hebrew Bible.
It is also essential to remember that traditional Jewish chronologies (since the beginning of the Jewish calendar almost 6,000 years ago) are based on the highly accurate astronomical phenomenon of the moon orbiting the earth (months) and the earth around the sun (years). This gives traditional Jewish chronology a high degree of accuracy, especially when it comes to the major events of Jewish history.
Actually, the "secular" calendar has experienced many difficulties in trying to properly "align itself with the stars." Back in 46 BCE, the calendar had become hopelessly confused. Julius Caesar was forced to abandon the previous lunar system, replacing it with a tropical year of 365.25 days. Further, to correct the accumulation of previous errors, a total of 90 intercalary days had to be added to 46 BCE, meaning that January 1, 45 BCE, occurred in what would have been the middle of March.
Over the next 1,600 years, the disagreement between the Julian year of 365.25 days and the tropical year of 365.242199 gradually produced significant errors. The discrepancy mounted at a rate of 11 minutes 14 seconds per year - until it reached a full 10 days. In 1582, Pope Gregory XIII proclaimed that 10 days should be skipped in order to bring the calendar back into line. This was accomplished by designating that October 5 become October 15. In other words, the dates October 5-14, 1582 were simply eliminated.
So how do we get the chronology that historians use today?
Historians in the late 19th and early 20th centuries worked backward and pieced it together. This was done primarily through comparing what little historical records survived from ancient Rome, Greece, Mesopotamia and Egypt, together with archaeological finds and radio carbon dating.
Because there are margins of error in all of these methods and much is open to interpretation, significant debates erupted between different scholars which continue to this day. Therefore, the chronologies used by modern historian can best be described as well-educated guesses.
Jewish chronology makes a stronger case for historical accuracy, and that's why we have chosen to use the traditional Jewish dates.
Today there are a number of renowned scholars also challenging the modern chronology and even attempting to reconcile it with the Jewish chronology. Amongst them is British scholar Peter James who writes: "By redating the beginning of the Iron Age in Palestine from the early 12th century BCE to the late 10th, a completely new interpretation of the archaeology of Israel can be offered: One which is in perfect harmony with the biblical record." ("Centuries in Darkness" by Peter James; Rutgers University Press, 1993, p. 318.)