Nissan 1 Jewish Calendar. Start of month of nisan on the hebrew calendar. The first commandment given to the newly born nation of israel before the exodus from egypt was:

Taanit esther, purim, shushan purim, shushan purim meshulash. נִיסָן (transliterated nisan or nissan) is the 1st month of the hebrew year, has 30 days, and corresponds to march or april on the gregorian.