|Type||Bread (usually flat bread)|
|Variations||Matzo, roti, tortilla, and many others|
Unleavened bread is any of a wide variety of breads which are prepared without using raising agents such as yeast. Unleavened breads are generally flat breads; however, not all flat breads are unleavened. Unleavened breads, such as the tortilla and roti, are staple foods in Central America and South Asia, respectively.
Unleavened breads have symbolic importance in Judaism and Christianity. Jews consume unleavened breads such as matzo during Passover as commanded in Exodus 12:18. Per the Torah, the newly emancipated Israelites had to leave Egypt in such a hurry that they could not so much as spare time for their breads to rise, as such, bread which cannot rise is eaten as a reminder.
Canon Law of the Latin Rite of the Roman Catholic Church mandates the use of unleavened bread for the Host, and unleavened wafers for the communion of the faithful. The more liturgical Protestant churches tend to follow the Latin Catholic practice, whereas others use either unleavened bread or wafers or ordinary (leavened) bread, depending on the traditions of their particular denomination or local usage.
On the other hand, most Eastern Churches explicitly forbid the use of unleavened bread (Greek: azymos artos) for the Eucharist. Eastern Christians associate unleavened bread with the Old Testament and allow only for bread with yeast, as a symbol of the New Covenant in Christ's blood. Indeed, this usage figures as one of the three points of contention that traditionally accounted as causes (along with the issues of Petrine supremacy and the filioque in the Niceno-Constantinopolitan Creed) of the Great Schism of 1054 between Eastern and Western churches.