The first three hundred years of the common era witnessed critical developments that would become foundational for Christianity itself, as well as for the societies and later history that emerged thereafter. The concept of 'ancient Christianity,' however, along with the content that the category represents, has raised much debate. This is, in part, because within this category lie multiple forms of devotion to Jesus Christ, multiple phenomena, and multiple permutations in the formative period of Christian history. Within those multiples lie numerous contests, as varieties of Christian identity laid claim to authority and authenticity in different ways. The Cambridge History of Ancient Christianity addresses these contested areas with both nuance and clarity by reviewing, synthesizing, and critically engaging recent scholarly developments. The 27 thematic chapters, specially commissioned for this volume from an international team of scholars, also offer constructive ways forward for future research.