Syncellus and other late writers[896] are our only extant sources for the statement that Diocletian burned the books of the alchemists in Egypt, so that they might not finance future revolts against him. If the report be true, one would fancy that the imperial edict would be more effective as a testimonial to the truth of transmutation in encouraging the art than it would be in discouraging it by destroying a certain amount of its literature. Thus the edict would resemble the occasional laws of earlier emperors banishing the astrologers—except their own—from Rome or Italy because they had been too free in predicting the death of the emperor, which only serve to show what a hold astrology had both on emperors and people. But the report concerning Diocletian sounds improbable on the face of it and must be doubted for want of contemporary evidence. Certainly we are not justified in explaining the air of secrecy so often assumed by writers on alchemy as due to the fear of persecution which this action of Diocletian[897] or the fear of being accused of magic aroused in them. Persons who wish to keep matters secret do not rush into publication, and the air of secrecy of the alchemists is too often evidently assumed for purposes of show and to impress the reader with the idea that they really have something to hide. Sometimes the alchemists themselves realize that this adoption of an air of secrecy has been overdone. Thus Olympiodorus wrote in the early fifth century, “The ancients were accustomed to hide the truth, to veil or obscure by allegories what is clear and evident to everybody.”[898] Nor can we accept the story of Diocletian’s burning the books of alchemy as the reason why none have reached us which can be certainly dated as earlier than the third century. [Sidenote: Alchemists’ own accounts of the history of their art.]