Michael is an archangel, who is only mentioned by name in the Old Testament in the Persian context of the post-Exilic Book of Daniel. According to Rabbi Simeon ben Lakish (230-270 CE), all the specific names for the angels were brought back by the Jews from Babylon, and many modern commentators would assent. Some believe that Michael was the Jewish version of the Zoroastrian Mithras.
According to rabbinic Jewish tradition, Michael acted as the advocate of Israel, and sometimes had to fight with the princes of the other nations. The idea that Michael was the advocate of the Jews became so prevalent that in spite of the rabbinical prohibition against appealing to angels as intermediaries between God and His people, Michael came to occupy a certain place in the Jewish liturgy. Much of the late Midrash detail about Michael was transmitted to Christian mythology through the Book of Enoch whence it was taken up and further elaborated. In Christian belief, Michael is the prince who fights with the devil.