This chapter discusses the era of the two important figures Aphrahat and Ephrem. It is in fourth century, and in these two writers, that the special character of 'Syriac exegesis' has often been looked for and found. The way that Syriac biblical exegesis developed in the fifth century was in part a consequence of the curriculum of the so-called 'school of the Persians' in Edessa. Narsai's chief literary output was of verse memre of which 81 survive. These show Narsai as a dedicated interpreter of the Bible. Narsai's adherence to Theodore, and departure from earlier Syriac norms, may also be seen in his suspicion of typology and references to Old Testament prophecy fulfilled in Christ. Jacob of Serug was also a student in the school of the Persians in Edessa, but he was resistant to the dyophysite christology taught there.