The studies on the history of the notion of “personhood” have largely recognized that Christian thought had a central role in the development and significance of this concept throughout the history of Western civilization. In late antiquity, Christianity used some terms taken from the classic and Hellenistic vocabulary in order to express its own theological content. This operation generated a “crisis” of classical language, namely a semantic transformation in the attempt to address some aspects of reality which were not envisioned (...) by the previous usage of these words. The term person is a paradigmatic example of this process. In fact, from the outset, it played a strategic role in formulating the idea of Incarnation, one of the central doctrines of Christianity. This essay aims to show how, during the first centuries of Christianity, the terms commonly used in order to express the notion of “personhood” became pivotal elements for the formulation of the discourse about the Trinity and progressively acquired new meanings. The analysis focuses only on the initial stage of the elaboration of this concept in Christianity and, based on some of the most significant texts, tries to bring out a series of theoretical problems that may be useful to understand the subsequent debate. In order to do so, the author divides the text in two parts. In the first one, he analyses two features strictly connected to the theological use of the term “persona”, which remained central also when this term was later referred to man. These features are individuality and ontological stability, along with the structurally relational status of personhood. In the second part, the author offers more details about the theology of the Cappadocian Fathers, in particular of Basil of Caesarea, and analyses two sectorial languages—mathematical and iconic language—used by Basil in order to describe the intra-trinitarian relationships. (shrink)