Emmer wheat may be one of the grains mentioned in ancient rabbinic literature as one of the five grains to be used by Jews during Passover as matzah (that is, kept from leavening, even accidental). However, this depends on the meaning of the Hebrew term "shibboleth shu'al," which is uncertain and debated. The matter is further complicated by the cultivation of spelt (Heb. "kusemet", Aramaic "kusmin") in Israel of Biblical times and onward (spelt is easily confused with emmer). However, it is fairly certain that spelt did not grow in ancient Israel, and emmer was probably a significant crop until the end of the Iron Age. Likewise, references to emmer in Greek and Latin texts are traditionally translated as "spelt," even though spelt was not common in the Classical world until very late in its history.