One of the most intriguing questions for the historian of early Christianity is the way that Christians conquered the entire Roman Empire. It has to be noted that the new religion started with a dozen people from rural areas of Palestine in 30 C.E. whose leader was just executed in a most humiliating way imagined. Fast forwards to 380 C.E. and Christianity is the official religion of the state with more than 50 % of the population. Still, this question remains an “open book” – scholars who spend their entire lives studying this phenomenon continue to find it surprising. Why did this minor religion from the eastern Mediterranean – marginal, despised, discriminated against – grow substantially, eventually supplanting the well-endowed, respectable cults that were supported by the state and aristocracy? The growth of the Christian church in the Roman Empire is still, as one recent study emphasized, mysterious. In this post, I’ll try to “pick the lock” of this interesting question.

Contrary to what many people seem to imagine, the Christian church grew quite slowly in its early years. At the end of the first century, there were probably no more than 10 000 Christians in the world, fewer than 0,2 % of the empire’s population of 60 million. But the church had a steady growth – it constantly grew not by evangelistic campaigns and massive conversions but via close social networking: a person who converted would talk about its new faith to his co-workers, family members, and friends. With something like 30 or 35 % of growth per decade (a rate that sociologists observed in new religious movements of the 19th and 20th centuries such as Mormons or Jehovah’s witnesses), the small circle of Jesus’ followers came to number three or four million by the end of the 2nd century. And then at the beginning of the 4th century, Constantine converted which gave the church a powerful ally. Several decades later, Christian emperor Theodosius the Great made Christianity the official religion of the empire only to embark on the quest to destroy the remnants of paganism – a task that proved to be more difficult than he could imagine.

But in the early years, what made people decide to give up other forms of worship to accept the Christian God? Why would a trader from Corinth in the 2^nd century, who worshiped state gods all of his life, suddenly reject paganism and embrace Christianity? Older studies claimed that it was because of a widespread spiritual “void”  throughout the empire, that the old gods were no longer considered worthy of worship and that Christianity arrived on the scene at just the right moment. The problems with this theory are numerous. First of all, archeological evidence uncovered in the last 50 or so years shows that pagan religions were actually thriving in the second and third centuries, with no signs of weakness or malaise. Secondly, this theory only begs the question: Why Christianity and not some other mystery religion? There was an explosion of popularity of several mystery religions such as the cult of Isis or Mithras. Why did the empire become Christianized, and not (for example) “Mithranized”? Also, there is the problem of the literary sources as well. Most of the evidence of the malaise of paganism comes from the Christian sources who are more than biased toward this idea that Christianity came into this world at the right moment according to God’s majestic plan. Historians can’t take these sources at their face value.

Other scholars came to different solutions. Some of them took the old notion of Tertullian (3^rd century) who wrote in one of his works: semen est sanguis Christianorum. On the basis of that, they concluded that the persecution of Christians actually made Christianity more attractive. One example of this is Keith Hopkins who comes close to romanticizing when he says that “in terms of number, persecution was good for Christianity”. This theory assumes that the courage of the martyrs astonished the Romans who then converted to Christianity. There are, however, good reasons to be cautious of taking Tertullian’s statement at face value. In reality, we have no unbiased sources to inform us about the impression made by the martyrs. Even in the hagiographical literature people coming to faith when they saw the Christian martyrs is not a common feature. For most outsiders the Christian martyrs were not only “crazy fanatics”, they were traitors threatening the order and stability of the Empire. We can see a glimpse of how an intellectual elite of the Empire saw this phenomenon when we look at Marcus Aurelius and his impressions on the Christians who are willing to die rather than sacrifice on the altars of pagan gods. He is astounded – he can’t believe their stubbornness. Far from being amazed by their bravery, Aurelius thinks that these Christians are lunatics. Furthermore, unlike the modern opinion, persecution of Christians in the Roman Empire rarely occurred. According to W. H. C. Frend, the number of martyrs was in “hundreds, not thousands”.  But the biggest problem with “semen est sanguis Christianorum theory” is the problem of apostasy and backsliding. It is something that is seldom taken seriously in a scholarly world. However, the church experienced apostasy from the very beginning. There are numerous traces in our sources (which I plan to examine in the next scholarly article) that points to the Christians who abandoned their faith in the face of persecution. It is a dark side of the cult of martyrs – a side that is often overlooked by critical scholars.

So, what is the answer? Why did Romans convert to Christianity? What made Christianity special? There is a possible answer provided first by a famous classicist Ramsay MacMullen (recently advocated also by Bart Ehrman who slightly remodeled it). According to them, Christianity possessed two crucial features that made all the difference in the world of the Roman Empire:

1. Evangelization – Christianity was a missionary religion from the start. No other religion in the Roman Empire had the kind of missionary impulse that Christianity had. Not even Judaism, as Martin Goodman explained. There is actually very little evidence to suggest that Jews actively sought converts. We don’t have anything like Paul in Judaism – an individual who goes from location to location spreading the news of his new faith. Similarly, different forms of paganism didn’t share the missionary impulse . It would be counterintuitive since in paganism you could worship as many gods as you wanted.
2. Second crucial feature is the exclusiveness of Christianity.  The Christian God was not normally chosen as one of the gods to be worshiped. The choice in this case was exclusive. Unlike the pagan forms of worship, Christianity emphasized the notion of exclusivity. You couldn’t follow numerous gods. Either you follow Christ and his Father or you don’t belong in the Christian community. Scholars have known this for a long time. At the beginning of the 20^th century, Arthur D. Nock wrote his master piece Conversion. In it, Nock argued that the basic difference between pagan religions and Christianity was the difference between “adhesion” and “conversion”. Within paganism, one could always add new set of religious practices. But that wasn’t conversion since a person could also continue in adhering to the old religious practices. There was no sense that a person who turned to a new cult had to turn away from another. In Christianity one cannot drink the cup of the Lord and the cup of demons too; you cannot have a part in both the Lord’s table and the table of demons (1 Cor 10,21).

Judaism was exclusive, but it wasn’t a missionary religion – not in the sense Christianity was. Furthermore, Judaism remained “trapped” inside of its own ethnic boundaries. If you wanted to convert to Judaism, you had to first “become” a Jew – which entailed a strict observation of the Old Testament laws such as the Kosher food and (for male candidates) circumcision. Meanwhile, all that Christianity asked of you is to surrender your life to Christ and believe in his redemptive death and resurrection. You could remain within your ethnic background (Roman, Greek, Egyptian, etc.) and be a Christian. As Paul wrote in the middle of the 1st century: There is neither Jew nor Greek, slave nor free, male nor female, for you are all one in Christ Jesus. With those two features Christianity, as Martin Goodman notes, entered the race of whose existence most of the other competitors were unaware. In a race where is only one competitor, the result is inevitable.