Christians of the second and third centuries held a remarkably wide range of beliefs. Although some of these beliefs may sound ludicrous today, at the time, they seemed not only sensible but right. Some Christians maintained that there were two Gods, or twelve, or thirty, or more. Some Christians claimed that Jesus was not really a human being, or that he was not really divine, or that he was two different beings, one human and one divine. Some Christians believed that this world was not created by the true God but by a malicious deity as a place for punishment for human souls, which had become entrapped here in human bodies. Some Christians believed that Jesus’ death and resurrection had no bearing on salvation, and some Christians believed that Jesus had never actually died.

Lost Christianities is a course that considers the varieties of belief and practice in the early days of Christianity, before the church had decided what was theologically acceptable and determined which books should be included in its canon of Scripture. Part of the struggle over belief and practice in the early church was over what could be legitimately accepted as "Christian" and what should be condemned as "heresy." This course considers the struggle fororthodoxy (that is, right belief) and the attempt to label, spurn, and overthrow heresy (that is, false belief). In particular, it tries to understand Christians who were later deemed heretical on their own terms and to explore the writings that were available and could be appealed to in support of their views.

Christians today, of course, typically think of the New Testament as the basis for a correct understanding of the faith. But what was Christianity like beforethere was a New Testament? It is striking that all the ancient Christian groups, with their distinctive views about God, Christ, salvation, and the world, had books that—like those that eventually came into the New Testament—claimed to be written by Jesus’ own apostles. Some of these pseudepigraphical(that is, falsely ascribed) books have been discovered by archaeologists and rummaging bedouin in Egypt and the Middle East in modern times, gospels, for example, that claim to be written by Jesus’ disciples Peter, Thomas, and Philip. These pseudepigrapha portray a different understanding of Christianity from the one that became dominant in the history of the religion and is familiar to most people today. In this course, we will study these non-canonical books and the forms of Christian belief they represent, from the second and third centuries—that is, from the time soon after the death of Jesus’ apostles up to the time when most of these earlier understandings of Christianity had been weeded out of the church, leaving the one form of "orthodoxy" that became triumphant in the early fourth century with the conversion of the Roman emperor Constantine.

The course is divided into several components. After an introductory lecture that deals with the wide diversity of Christianity in the modern and ancient worlds, we will launch into a discussion of three forms of Christianity that were highly influential during the second and third Christian centuries: the Ebionites, a group of Christians who insisted on maintaining their Jewish identity while believing in Jesus; the Marcionites, a group that rejected everything Jewish from its understanding of Jesus; and the Gnostics, a wide-ranging group that understood this world to be an evil place of imprisonment from which one could escape by learning the truth of one’s identity through the secret teachings of Jesus.

We will then begin to consider, in separate lectures, important books read and revered by each of these groups and by the group that represented the forebears of the kind of Christianity that eventually became dominant in the Empire, a group that we will label "proto-orthodox" (because they held to the views that eventually came to be declared orthodox). Many of these books are pseudonymous, forged in the name of one or another of the apostles. Included in our consideration will be "Gnostic Gospels," such as the Gospel of Thomas; "Infancy Gospels," which narrate fictional events from Jesus’ life as an infant and young boy; Apocryphal Acts, which describe the entertaining escapades of several of Jesus’ apostles (including the woman, Thecla) after his death; apocryphal epistles allegedly written by the apostle Paul and others; and one apocryphal apocalypse, a description of a guided tour of heaven and hell given to the apostle Peter by Jesus himself.

After considering these fascinating documents, many of which have come to our knowledge only during the twentieth century, we will turn to consider the conflicts among the various forms of Christianity in the early centuries, to see how it is that one understanding of the faith came to be dominant and to squelch all its opposition. In this final section of the course, we will consider how the proto-orthodox party invested ecclesiastical power in its clergy (forming the structure and hierarchy that became a mainstay of the church through the Middle Ages); developed its canon of Scripture (the New Testament, which was not finalized as a canon until the end of the fourth century); and formulated standard creeds (e.g., the Apostles’ Creed and the Nicene Creed) as statements of faith to be adhered to by all believers, thereby eliminating the possibility of alternative understandings of what it might mean to be a follower of Jesus.