Why did the early church in the West grow? This question has fascinated scholars and led to much debate—a debate that increasingly has to do with approaches to illness and medicine.

One approach common among eminent scholars highlights the early Christians’ prayers for divine miracles. Their exorcisms of demonic powers, these scholars claim, were often associated with healing of illnesses. According to Ramsay MacMullen, miracles were “the chief instrument of conversion” and are a primary explanation for the church’s growth.

A second approach, associated with sociologist Rodney Stark, highlights the medical care that was deployed by Christian communities. Stark concentrates on the early Christians’ response to the plagues that racked the Roman Empire from the second to the fourth century. In times of desperate danger, when up to a third of the populace was killed by pandemics, Christian congregations provided elementary nursing (presence, bread and water) to seriously ill people, both Christians and non-Christians. This care led to the deaths of some Christian caregivers, but also to the survival of many patients—and to the growth of the church.

Into this debate steps Gary B. Ferngren, professor of ancient history at Oregon State University and a world authority on medicine and illness in the Greco-Roman world. His book Medicine and Health Care in Early Christianity has moved the debate forward.

Ferngren compactly and authoritatively surveys three areas of healing practices in the ancient world. He describes the miraculous “religions of healing,” such as the cult of Asclepius. He surveys popular magical practices, such as the use of amulets and incantations. And he especially concentrates on the “naturalistic” medicine that was developing among Greek intellectuals and practitioners, notably Hippocrates and Galen. It was with the natural medical arts, Ferngren argues, that the early Christians felt most at home. It is true that early Christians engaged in exorcism, but rarely in connection with healing; according to Origen, in the third century only “traces” of the Holy Spirit’s healing work were still present in the church. The early Christians responded to illness with medicine, not miracles, he contends.

The early Christians’ response, ex plains Ferngren, was corporate rather than individual. All members, not simply designated specialists, were to visit believers who were poor and sick. This congregational approach was seen in full operation during the plague of 252, when Bishop Cyprian urged the Christians in Carthage to provide basic medical assistance for sick Christians and for sick pagans as well.

Such an approach to illness was “unique in the classical world.” It was rooted, Ferngren contends, in Christian theology. The early Christians believed that humans were created in the divine image and therefore were intrinsically precious and worthy of care. The God who created humans treated them with love and mercy through Christ’s incarnation and saving work; and God then asked Christians—in ways that had no pagan parallels—to respond ethically by extending love and mercy to others. Pagan religions had ritual requirements, but they had no ethical overflow that responded to divine, self-giving love. Compassion was a central value to the Christians, and the Christians’ anticipation of a life of eternal felicity lessened their fear of dying and equipped them to risk infection as they cared for the sick.

As Christians became more numerous after Constantine legalized the faith in the fourth century, changes occurred. Earlier Christian approaches to healing led to a professionalization of medical care and the development of new curative institutions, namely hospitals. Miracu lous events proliferated: far more than earlier, Christians claimed divine healing through exorcistic rites, holy people and relics. And as Christians spread geographically and uncritically became enculturated in their societies, they began to resort to practices that they had earlier repudiated—using amulets, reciting incantations.

The shape of Ferngren’s argument is essentially correct. His scholarship is impressive, and he writes lucidly in a way that allows him to communicate to nonspecialists. But his tilt away from the miraculous seems greater than the sources allow. Origen’s talk about “traces” must be balanced with his participation in an exorcism in the midst of a catechetical session. “Things like this,” Origen commented, “lead many people to be converted to God, many to reform themselves, many to come to faith.”

I am also troubled by Ferngren’s casual reading of the church orders—leaders’ handbooks that are informative about church practice. On the one hand, these intensify Ferngren’s point about the responsibility of all believers to care for the sick. The church orders did not simply privately encourage ordinary Christians to “visit the sick and aid the poor”; they made this a core Christian practice that was taught in catechesis. When presenting candidates, sponsors were asked: “Have they visited the sick?” Only if the catechumens had engaged in this practice were they admitted to baptism. The church orders also assumed that miraculous healing was a normal part of church life. When believers claimed to have gifts of healing, this had to be tested in practice; did the people they prayed for recover? And according to the church orders, the bishop had a healing role; his visit could relieve a person of sickness, especially if he prayed for the one who was ill. These practices place a question mark over Ferngren’s downplaying of miracles.

Finally, Ferngren ignores the miraculous scenes in early Christian visual art. Repeatedly the art depicts Jesus as a healer—of the leper, the blind man, the woman with a flow of blood. These scenes were commissioned by communities that believed, as the church orders indicate, that miraculous healing was a part of their church’s life.

So why did the early church grow? Ferngren’s preferred reason is not miracles but “argument, persuasion, and a theology that brought conviction and hope.” I think that the evidence he provides for the Christians’ respect for naturalistic medicine, leading to their congregations’ care for the sick, adds another reason—the Christians’ fascinating behavior. Though there may be more evidence in the sources for miracles than Ferngren allows for, the story that he tells is provocative for Christian readers who live in a culture of fear and who tremble at the thought of new pandemics.