Due to the diverse types of calendars and dating systems in
existence among the various territories in biblical times, a
good working knowledge of various calendar systems is a
pre-requisite for gaining a fuller understanding of Bible
dating methods. We’ll begin with a brief look at the
various calendar components and types.
By “components”, we mean the ingredients or
elements that are common to all calendars, yet also
differentiate a particular calendar system (such as the
Hebrew, Roman, Julian, Gregorian etc) from others.
The first of two major components is the calendar’s
“type”. This is defined by the purpose and
basis of its annual cycle, and the quantity and makeup of
its months and days.
The other chief factor is the calendar’s point or
date of origin, such as the Creation, founding of a
nation, reign of a famous leader, or any other event from
which subsequent years are numbered. In some calendar
dating systems, years removed from this origin are typically
assigned a descriptor such as BC, AD, BCE, CE, AUC etc;
while in others the years are simply designated in the form
of, for example “the 15th year of the reign of King
Solomon”. Most dating systems can be applied to the
different calendar types. We’ll address the dating
element throughout the article, but we now further expound
on the first component.
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Almost all calendars are based on astronomical cycles and
can be grouped according to three basic types: “solar”, “lunar”, or “lunisolar”.
Lunar calendars are based upon the moon’s rotation
about the earth from New Moon to New Moon (the Hebrew word for moon,
chodesh is also translated as “new moon”). During this one
“lunation” or “synodic month”, the moon will completely circle the earth
in about 29.5 days (lunar year = 354 days). A solar
calendar is based on the earth’s motion around the sun.
One complete average orbit takes a small fraction less than 365.25 days
and is known as a “tropical year”. This orbit is measured from two
consecutive fixed points, usually the northern vernal equinox which
denotes the beginning of spring in the northern hemisphere.
The primary benefit of the solar calendar is in its synchronization with
the seasons. This can be a critical advantage when we consider the
many industries that are so closely tied to certain seasons occurring at
certain times of the year. The lunisolar calendar
attempts to bridge the difference somewhat by following the lunar cycle,
but adding additional days to certain months or by adding an additional
month every few years. These leap days or months are sometimes
referred to as “Intercalate” Days or Months.
For example, the lunisolar Julian calendar (beginning under Roman
Emperor Julius Caesar) has 12 months of 30 or 31 days with February at
28 days, or 29 days on leap years. Even with these adjustments
however, it would eventually be almost globally replaced by the more
accurate solar based Gregorian calendar, as we will see in the “Modern
Calendar” chapter in part 4. We can also note that many of the solar
calendars published today add the various lunar phases, thus further
reducing the need for an exclusively lunar calendar.
In Part 2 - Calendars during Bible Times, we’ll explore the political and historical context of the major nations
in which the various calendar systems developed during
the biblical era and the early church period.
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