However, scholars have noted that long before the Jews celebrated Passover, farmers of the Middle East celebrated Chag Ha-matsot, the festival of unleavened bread, at this time of year. This was a festival where unleavened bread was made from the new grain harvest that took place at this time of the year        

    The old fermented dough was thrown out so that last year's grain would not be mixed with this year's. Therefore, the new season began with the eating of unleavened bread--matsah. Later on, the Jewish people incorporated this agricultural festival into the celebration of freedom and renewal we now call Passover.

haggadah Section: Motzi-Matzah
Source: Ezter Haggadah