The passage 25,1-3 in Athenagoras's Legatio pro christianis, a writing replete with Greek philosophical and mythological material, seems to represent a retelling of a Jewish narrative, both biblical and pseudo-epigraphic, namely the myth of the Watchers. A thorough investigation of the passage from Legatio discloses that Athenagoras's version of the myth is closest to the first version of the narrative, namely to the Book of the Watchers. At the same time, the Athenian introduces Greek philosophical terminology and problems within his retelling of the myth. However, the most significant discovery is the fact that Athenagoras, employing especially Stoic psychological terms, investigates the way the fallen angels act within the human souls. In this way, one may say that the Athenian internalized the myth and conferred on it a psychological analysis. He was probably the first to undertake this kind of investigation—before Clement, Origen, and especially Evagrius, the latter being the one who articulated the most elaborate analysis of the psychological effects of the demonic influences.