DELIBERATELY DIVERSE | by Francis Sorrow Caesar, a Pope and the Hebrew calendar
“ Deliberately Diverse” represents the individual thoughts and opinions of a group of Taylor friends who almost never completely agree about anything but are gratified by the opportunity to stimulate deliberately diverse discussions in our beloved community. Today’s column represents the thoughts and opinions of Francis Sorrow, a long-time resident of Taylor and student of Jewish history, not the Taylor Press.
What do Julius Caesar, Pope Gregory XII and the Hebrew calendar have to do with one another? It’s a centuries long story that still impacts the Jewish communities.
The result of this story makes it appear that the Jewish holidays are never on the same date. Actually, the holidays are always on the same date in the Hebrew calendar. For example, Hanukkah always starts on the 25th day of Kislev.
However, we also use the secular calendar, implemented by Julius Caesar. On that calendar, Kislev can start anywhere from late November to late December. Why? Unlike our secular calendar, which is based on the solar year of 365 1/4 days (plus a few odd minutes), the Hebrew calendar retains its ancient lunar biblical basis.
Hebrew months always start on the new moon. The 15th of the Hebrew month always falls at the full moon. There are 12 months of either 29 or 30 days in the year, so there are 11 less days in the lunar year than the solar year.
In 45 BCE, Caesar replaced the Roman lunar calendar with a new solar calendar to ensure that the calendar stayed aligned with the seasons. This calendar handles that quarter day by adding an extra day to February every four years. Thus, the Julian calendar was our secular calendar for around 1,600 years.
However, this didn’t align the shorter Hebrew religious year with the seasons. This Hebrew year requires more frequent adjustments to remain in phase with both the Bible and the solar year. Thanks to the astronomical work authorized by Julius Caesar, the rabbis used that data and their own work to adjust the Hebrew calendar.
They added an extra month seven times in the 19th year cycle that aligns the solar and lunar years. The extra month is added in the 3rd, 6th, 8th, 11th, 14th, 17th and 19th years of the cycle. This pattern ensures that Passover will always fall after the spring equinox (March 21). It starts on the first full moon after the equinox, the 15th day of Nissan.
How did a Pope get involved? Remember those odd minutes?
In 45 BCE, Caesar’s astronomers knew they existed but couldn’t figure out how to adjust for them.
By the 16th century, the calendar was out of phase with the seasons by 11 days. Pope Gregory XII added 11 days to the calendar. So, for Jews in the western world, our secular calendar is the Gregorian calendar. But England had already separated from the Roman Catholic Church and didn’t add the extra days until 1762, which adjusted American dates.
