With the Jewish festival of Passover approaching, I take the opportunity to bring some explanations about this important milestone in the Jewish calendar year. The festival starts on the 15th of the month of Nisan. The night before, on the 14th, Jews tell the Haggadah, which is the story of the exodus of their Hebrew ancestors from bondage in Egypt.
The month of Nisan
Hebrews used to call each month by a number, i.e. 1st month, 2nd month etc. (similarly to days: 1st day, 2nd day etc.) and Nisan was the "head" (i.e. the first) of the months, as instructed in Exodus 12:1-2: And the LORD spoke unto Moses and Aaron in the land of Egypt, saying: 'This month shall be unto you the beginning of months; it shall be the first month of the year to you.