Syriac culture was heir to three quite different literary cultures: ancient Mesopotamian, Jewish and Greek. In the period up to 425, elements from all three can be readily identified, in varying proportions, in the extant literature; from the early fifth century onwards the Greek element became the predominant influence, while the other two fade into the background. This applies equally to the history of Syriac culture in the Sasanian empire, although there the influence of Greek culture on Syriac literature does not become strong until the sixth century. The interaction between Greek and Syriac culture in Syria and northern Mesopotamia was in fact a complex affair, and in the period under consideration the juxtaposition of the two literary cultures resulted in mutual enrichment. In the sixth century, at a time when the prestige of Greek culture was resulting in ever stronger influence on Syriac literature, Syriac was actually gaining ground as a written language to the west of the Euphrates.