The Wrong Day for Pesach?

A calendar controversy in the tenth century, which was forgotten until it surfaced in the Cairo Genizah, meant that Jews in different communities celebrated Yom Tov on different days.

As Pesach approaches, Jewish communities everywhere race to prepare. But imagine if the Jews across town were still preparing for Pesach while you were sitting down to the Seder—because the two communities couldn’t agree on which day Pesach started.

The Jewish calendar has served as a unifier of the Jewish people for about a thousand years. But it was not always that way. In fact, in the year 922 CE, not all Jews observed Pesach on the same date. How could this be? you will ask; after all, sometime in the fourth century CE, the Jewish people stopped determining the calendar by lunar observation and instituted a calculated calendar. How could it be that Jews who followed the Babylonian Sages would observe Pesach and even Rosh Hashanah two days before their brethren in Eretz Yisrael?

Read the rest of The Wrong Day for Pesach? in Ami Magazine.