From Wikipedia:

Emmer wheat is mentioned in ancient rabbinic literature (as one of the five grains forbidden to Jews during Passover). It is often incorrectly translated as spelt in English translations of the rabbinic literature but spelt did not grow in ancient Israel and emmer was 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.

Take that, Ezekiel 4:9.