Proponents of the so-called "copycat" theory of Christian origins allege that Christianity is a myth based on the appropriation of various pagan beliefs. The most common source of beliefs supposedly borrowed is Mithraism. The alleged similarities between Christianity and Mithraism are usually overblown or distorted, but perhaps an even bigger weakness of the theory is timing. Simply put, Mithraism cannot be a source for Christianity if it came later.
As an initial matter, it can be difficult to establish parallels because of the fundamental differences between Christianity and Mithraism. Christianity was an open evangelistic religion whereas Mithraism was a secret, mystery cult. Christians announced their core beliefs whereas Mithraism hid them. Christianity left behind a wealth of manuscript evidence, whereas Mithrasm left very little. One implication of this is that given the paucity of evidence about Mithraic beliefs, commentators are able to read into Mithraism what they want. And they often do.
Proponents of the copycat theory may point out that Mithra himself is an old god who predates Christianity. This may be true, but is beside the point. Mithra is an ancient god, part of Persian religious belief that does in fact predate Christianity. But this is not the religion copycat theorists typically compare to Christianity. Rather, the Mirthraism compared to Christianity is Western or Roman Mithriasm. It is one of the mystery religions typical of the period that borrowed Eastern names but had little else in common with its forerunner. As recognized at the First International Congress of Mithraic Studies, Roman Mithriasm -- the mystery religion version -- was “a new creation using old Iranian names and details for an exotic coloring to give a suitably esoteric appearance to a mystery cult.” John R. Hinnells, Mithraic Studies: Proceedings of the First Int’l Congress of Mithraic Studies, page xiii.
Accordingly, it is important to isolate the supposed religion of comparison. It is not enough to say that certain rites or beliefs were associated with Mithra and assume they must all predate Christianity because Mithra did. Not at all. Once must be careful to recognize the different strains of Mithraism and track the development of each supposed parallel. Persian Mithra and Western Mithraism were in essence two different religions.
One can find extensive lists of supposed parallels between Christianity and Mithraism. These lists are problematic for a number of reasons. It is beyond the scope of this post to discuss them all, but a few examples will reveal some of the common errors.
It has been argued that both Jesus and Mithra were born of a virgin. The earliest Christian attestations are in the Gospels of Mark and Luke, both written in the first century. Bishop Ignatius of Antioch also writes of Jesus’ virgin birth early in the second century. All agree that Jesus’ mother conceived him as a virgin. However, there are no references to Mithras being born of a virgin. Rather, the most common story of Mithra’s origins is that he emerged fully grown from a rock. There is no evidence of a virgin birth for Mithra, unless one really stretches the point and claims that rocks are inherently virgins. This is a common failing of the copycat enthusiasts and something to closely examine. Do not simply take these assertions at face value, request citations to actual evidence that Mithriasm had particular beliefs.
It has been argued that both Jesus and Mithra share the same birthday, December 25. It may be true that Mithra is associated with December 25, but this hardly proves the point. The earliest recorded date celebrated for Jesus’ birth day is January 6, as it is still observed in many Orthodox churches. The December 25 date was established probably by Constantine because of the popularity of Sol Invictus in the fourth century. It is unlikely Mithraism was the reason for selecting this date, as it was already significant. In any event, some copying 300 years after Jesus' life and 250 years after the writing of all of the New Testament documents does not prove the copycat theory. This is yet another common failing of the copycat enthusiasts. Establishing a similarity that can only be traced to hundreds of years after Christianity was well established proves nothing.
It has been argued that Mithra celebrates a sacred meal much like the Last Supper. This is so general as to be a worthless point of comparison when discussing origins. Moreover, there is an obvious precursor to the Christian meal, the Passover Meal. The ignoring of obvious Jewish elements of Christian belief while grasping for unlikely pagan parallels is a common error of the copycat enthusiasts. “The ritual meal was probably simply a component of regular common meals. Such meals have always been an essential part of religious assembly; eating and drinking together creates community and renders visible the fact that those who take part are members of one and the same group.” Manfred Clauss, Roman Cult of Mithras, page 113. More specifically, the Christian meal “is centered in the Jewish tradition of the Passover feast and the specifically historically recollections of Jesus’ last acts” while the meal in Mithraism “has its origins in Mazdean [Persians] ceremonies.” Gary Lease, “Mithraism and Christianity: Borrowings and Transformations, in Wolfgan Haase, ed., Aufsteig und Niedergang der Romischen Welt, Vol. 2, page 1324.
As discussed above, although loosely connected to a forerunner we can call Persian Mithraism, Mithraism as a mystery religion in Roman lands does not precede Christianity. In other words, Christianity and its core doctrines came first. Thus, it cannot be the result of Mithraism. The Pauline corpus was written from approximately 49 to 60 AD. The canonical Gospels were written before the end of the first century, likely from approximately 60 AD to 90 AD. The core beliefs of Christianity, therefore, were literally in writing by the mid-first century.
The origins of Western Mithraism, on the other hand, are best traced to the second century. “The flowering of Mithraism occurred after the close of the New Testament canon, too late for it to have influenced the development of first-century Christianity.” Ronald Nash, Gospel and the Greeks, page 137. See also Edwin Yamauchi, Persia and the Bible, page 510 (“It is therefore reasonable to argue that Western Mithraism did not exist until the mid-second century, at least in a developed sense.”). Even if we grant Mithraism several decades, it still is an implausible candidate for influencing Christian origins. If one finds the parallels irresistible, it would be more reasonable to conclude that Mithraism copied Christianity -- as some ancient Christian apologists alleged.
Given the failure of the parallels and the fact that Christianity precedes Western Mithraism and its associated beliefs, the best conclusion is that Mithraism fails as a candidate for the copycat theory of Christian origins. As one Mithraic specialist concludes:
After almost 100 years of unremitting labor, the conclusion appears inescapable that neither Mithraism nor Christianity proved to be an obvious and direct influence upon the other in the development and demise or survival of either religion. Their beliefs and practices are well accounted for by their most obvious origins and there is no need to explain one in terms of the other.
Gary Lease, “Mithraism and Christianity: Borrowings and Transformations," in Wolfgan Haase, ed., Aufsteig und Niedergang der Romischen Welt, Vol. 2, page 1316.