Modern knowledge of Didymus has been greatly increased by a group of 6th or 7th century papyrus codices discovered in 1941 at a munitions dump near Toura, Egypt (south of Cairo). These include his commentaries on Zechariah, Genesis 1-17, part of Job and parts (of uncertain authenticity) on Ecclesiastes and Psalms 20-46. In these commentaries, Didymus discusses long quotations from the Bible, and refrains from speculation, which he considered sophistry. However, he interprets scriptures allegorically, seeing symbols everywhere. For example, he wrote that the mountains in Zachariah represented the two Testaments of the Bible. Didymus saw an individual's movement towards virtue as emerging from their interaction with scripture.