How and when did Jesus and the Spirit come to be regarded as fully God? The Birth of the Trinity offers a new historical approach by exploring the way in which first- and second-century Christians read the Old Testament in order to differentiate the one God as multiple persons. The earliest Christians felt they could metaphorically 'overhear' divine conversations between Father, Son, and Spirit when reading the Old Testament. When these snatches of dialogue are connected and joined, they form a narrative about the unfolding interior divine life as understood by the nascent church....