The spread of culture has been often paralleled with epidemic contagion. We propose to use models of this type to analyze Romanization and Christianization through onomastic data (names). We first examine the spread of Romanity in the ancient Greek world, and then the spread of Christianism, through the dynamics of Roman and Christian names acquisition. The dynamics of the transition from a pure Greek world to a Romanized world appear to have been fundamentally driven by an intense adoption of Romanity combined with an equally intense return to traditional Greek names. The transition from pagan to Christian names, on the other hand, was more permanent, leading to a more explosive acquisition pattern.