This comprehensive study offers a critical, comparative analysis of the sources available on Bardaisan and a reinterpretation of his thought. The study highlights the profound points of contact between Bardaisan, Origen, and their schools; the role of Plato’s Timaeus and Middle Platonism in Bardaisan’s thought, and Stoicism. Bardaisan’s thought emerges as a deeply Christian one, depending on the exegesis of Scripture read in the light of Greek philosophy. Positive ancient sources present him as a deacon or even a presbyter, as an author of refutations of Marcionism and Gnosticism, and as a confessor of the faith during persecution.