With the conversion of Constantine in 312, Christianity began a period of political and cultural dominance that it would enjoy until the twentieth century. Jacob Neusner contradicts the prevailing view that following Christianity's ascendancy, Judaism continued to evolve in isolation. He argues that because of the political need to defend its claims to religious authenticity, Judaism was forced to review itself in the context of a triumphant Christianity. The definition of issues long discussed in Judaism—the meaning of history, the coming of the Messiah, and the political identity of Israel—became of immediate and urgent concern to both parties. What emerged was a polemical dialogue between Christian and Jewish teachers that was unprecedented.

In a close analysis of texts by the Christian theologians Eusebius, Aphrahat, and Chrysostom on one hand, and of the central Jewish works the Talmud of the Land of Israel, the Genesis Rabbah, and the Leviticus Rabbah on the other, Neusner finds that both religious groups turned to the same corpus of Hebrew scripture to examine the same fundamental issues. Eusebius and Genesis Rabbah both address the issue of history, Chrysostom and the Talmud the issue of the Messiah, and Aphrahat and Leviticus Rabbah the issue of Israel. As Neusner demonstrates, the conclusions drawn shaped the dialogue between the two religions for the rest of their shared history in the West.