Motives of Credibility: The Growth of the Church

The reader who surveys the New Testament could be forgiven for thinking the growth of the Church in the first century was a series of explosive mass conversions. A post-Ascension community of about 120 persons (cf. Acts 1:15), the Church in swift order added about 3,000 after St. Peter’s Pentecost homily (cf. Acts 2:41). Not long after, the total number of Christians jumped to about 5,000 (cf. Acts 4:4). By the conclusion of the Book of Acts, Christian missionaries won converts among a diverse variety of peoples of the Near East, Africa, Asia Minor, Greece, and even Rome. The letters of St. Paul further suggest that Christian communities popped up throughout the Roman Empire, practically overnight.

It must have appeared that way to the earliest Christians. In a few short decades, a fledgling religious movement that seemed ready for extinction after the death of its messianic leader had made a remarkable turnaround, spreading in every geographic direction from its birthplace in Judea. Its adherents claimed their leader to be not only risen from the dead but literally God Himself, the eternal Logos. As witnessed at Pentecost, men and women both within and without the empire heard and believed that Gospel (cf. Acts 2:5-42).

Yet those dramatic events — even if historically accurate, and there is good reason to believe they are — may be somewhat deceiving. In The Rise of Christianity: A Sociologist Reconsiders History (1996), Rodney Stark, relying on the work of many other scholars, speculates that in A.D. 40, less than a decade after Christ’s Resurrection, there were around 1,000 Christians, amounting to 0.0017 percent of the population of the 60-million-strong Roman Empire. By the turn of the first century, Stark projects, there were fewer than 8,000 Christians, and by the middle of the second century a little over 40,000. As late as the middle of the third century, the theologian Origen admitted that Christians comprised “just a few” of the imperial population.

And then, remarkably, only six decades after Origen’s death, Christians were so numerous — probably about ten percent of the population — that the Emperor Constantine found it expedient to embrace the Church. Within another 50 years, Stark estimates, Christians likely represented a slim majority of the empire. “How did a tiny and obscure messianic movement from the edge of the Roman Empire dislodge classical paganism and become the dominant faith of Western civilization?” he asks. His (empirically based academic) answer is that Christianity offered a better and more secure way of life to its followers, one that spread through natural social networks. Christians exemplified an attractive degree of virtue, including a willingness to endure martyrdom, that appealed to people across class and culture. A consistent growth rate of approximately 40 percent per decade eventually resulted in a majority-Christian empire.