Athanasius repeatedly presents Asterius as the advocate (sunêgoros) of Arianism. This is commonly taken to mean that he judged Asterius to be prominent among those Eusebians who supported the cause of Arius in the years leading up to the Council of Nicaea and afterward. It is furthermore usually interpreted by scholars to mean that Arius, if not a source, was at least a foil for Asterius: Asterius defended Arius even as he developed his thought (e.g. Kopecek, Hanson). But Markus Vinzent has suggested that Asterius perhaps be called the "mentor" (Vordenker) of Arius. Given the shared themes in the theologies of Arius and Asterius, the question of influence in either direction cannot be resolved on the basis of similarity of teaching; external indications are needed. Vinzent's claim seems to be based only upon two passages in De decretis, in which Athanasius states that Arius borrowed from Asterius, not vice versa. Vinzent's claim has been noted by others, but has not generated any substantial comment. The purpose of this communication is to take up the topic which others have declined to treat. It takes two approaches. First, the paper briefly discusses whether the evidence of De decretis should be interpreted as a global statement of the theological relationship between Arius and Asterius. Second, the paper attempts to establish the relative chronology of the Syntagmation of Asterius and the Thalia of Arius, to gauge the possibility of Arius being influenced by the former text in the composition of the latter.