|Type||Bread (usually flat bread)|
|Variations||Matzo, roti, tortilla, and many others|
Unleavened bread is any of a wide variety of breads which are not prepared with 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 - various traditions explain this usage. Unleavened bread also features in some Western Christian liturgies during the Eucharist, a rite derived from the Last Supper when Jesus broke bread, naturally believed to have also been matzo, with his disciples during a Passover Seder.
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.