Book excerpt: We do not have many definitions of Christianity from late antiquity, but among the few extant is the brief statement of Gregory of Nyssa (335-395 CE) that it is "mimesis of the divine nature." The sentence is both a historical gem and theologically puzzling. Gregory was the first Christian to make the infinity of God central to his theological program, but how could he intend for humans to imitate the infinite? If the aim of the Christian life is "never to stop growing towards what is better and never to place any limit on perfection," how could mimesis function within this endless pursuit? In Imitations of Infinity, Michael A. Motia situates Gregory among Platonist philosophers, rhetorical teachers, and early Christian leaders to demonstrate how much of late ancient life was governed by notions of imitation. Questions both intimate and immense, of education, childcare, or cosmology, all found form in a relationship of archetype and image. It is no wonder that these debates demanded the attention of people at every level of the Roman Empire, including the Christians looking to form new social habits and norms. Whatever else the late ancient transformation of the empire affected, it changed the names, spaces, and characters that filled the imagination and common sense of its citizens, and it changed how they thought of their imitations. Like religion, imitation was a way to organize the world and a way to reach toward new possibilities, Motia argues, and two earlier conceptions of mimesis—one centering on ontological participation, the other on aesthetic representation—merged in late antiquity. As philosophers and religious leaders pondered how linking oneself to reality depended on practices of representation, their theoretical debates accompanied practical concerns about what kinds of objects would best guide practitioners toward the divine. Motia places Gregory within a broader landscape of figures who retheorized the role of mimesis in search of perfection. No longer was imitation a marker of inauthenticity or immaturity. Mimesis became a way of life.