Dealing with the question of monotheism, with which he begins the Divine Institutes, Lactantius declares his intention to overcome the difficulty of demonstrating the Christian truth to pagans, who have only disdain for the biblical text, through his recourse to the testimonia of (“pagan”) philosophers or poets, hermetica or oracles. First, we understand that the Bible remains the true “subtext” of Lactantius’ discourse, and that these texts are only cited as evidence because of the authority they enjoyed among the pagan readership. Second, and with a closer look at the illocutionary force of his discourse, we show that Lactantius is not only concerned with the concept of monotheism but also with its application to religion through worship. So, while these various testimonia make us sensitive to the intellectual environment of the time, it is ultimately Cicero who is revealed as the “counter-figure” of the apologist in his argumentation to his readers for the institution of the Christian religion.