My comparative mythology class textbook and professor teach that the Christian faith took some of its most significant elements from a Persian religion dedicated to Mithra. Is this true?
While Mithraism appears to have had many similarities to Christianity, it seems that Mithraism copied from Christianity, not the other way around. The Catholic Encyclopedia explains:
Our knowledge regarding Mithraism is very imperfect . . . mostly ingenious guesswork; of the real inner working of Mithraism and the sense in which it was understood by those who professed it at the advent of Christianity, we know nothing. . . . Some apparent similarities exist; but in a number of details it is quite probable that Mithraism was the borrower from Christianity.