Excommunicating the Faithful traces the development of Jewish Christianity from among the earliest Jesus followers through its apparent disappearance in the fourth or fifth century. The author’s thesis is that among Jewish Christians in the early Church, there existed at least one Jewish Christian sect whose theology stood within the acceptable boundaries of orthodoxy at that time and existed through at least the fifth century, at which point it was declared heretical by the Church Fathers and eventually died out despite the fact that it considered itself part of the greater Church. The author’s thesis also suggests that the increasing antipathy of the Church toward Jewish Christianity was the result of a variety of interrelated influences operating over several centuries. Some of these influences included the changing demographics of the Church and the accompanying clash of cultures; the increasing isolation of Jewish Christianity from the predominantly Gentile Church; power struggles between competing Christian communities in Palestine, as well as Rome’s interest in asserting its primacy; and theological and pastoral concerns, which were well-intentioned but resulted in increasingly narrow views of orthodoxy and orthopraxis; and lasting anti-Jewish sentiments throughout the Empire, some of which still exist today.