 In view of the drastic difference in subject matter it is possible that these represent the work of a different Didymos.The Stoic philosopher, Seneca, in his Epistulae Morales ad Lucilium claims that Didymus wrote four thousand books, while making a commentary on the acquisition of useless knowledge.Further insight into Didymus' methods of writing was provided by the discovery of a papyrus fragment of his commentary on the Philippics of Demosthenes.