Religious epics are subsumed under historical epics, written about religious figures or ceremonies. This kind of epic has long since produced very many examples, but the question of their formation, their features and their place in the Persian language and literature has not been addressed in a comprehensive way.In the present article, by reviewing the epics and its kinds, the manner of their development, characteristics and standing have been studied. It has been demonstrated, for instance, that the composing of religious epics does not merely result from the decline of national epics, and that even in the greatest national epic of Persians, namely Firdowsi's Shahnameh, kinds of epics (mythical, national, historical, and religious) all come together. Secondly, due to strong religious incentives, religious epics in Iran present numerous instances, each having their own features and qualities, though many of them are poor in language and diction and demonstrate clear indications of imitating Firdowsi.