Increasing attention has been paid in recent years to the complex of writings which goes under the name of Hermes Trismegistus. These Hermetic writings embrace not only a corpus of some fourteen tractates which has been preserved in continuous Greek manuscript form, but also fragments contained in the works of Stobæus and other writers, and finally the "Asclepius" attributed to Apuleius. It is not usually maintained that the Hermetic literature was completed before about 300 A.D.; no one claims anything like pre-Christian origin for the whole. The individual elements of the literature--for example, the individual tractates of the Hermetic corpus--are usually regarded as having been produced at various times; but no one of them is generally thought to have been written before the beginning of the Christian era. With regard to the most important tractate, the "Poimandres," which stands at the beginning of the corpus, opinions differ somewhat. J. Kroll, for example, the author of the leading monograph on the Hermetic writings, regards the Poimandres as the latest of the tractates in the corpus, and as having appeared not before the time of Numenius (second half of the second century);[158] whereas Zielinski regards it as the earliest writing of the corpus.[159] By an ingenious argument, Reitzenstein attempts to prove that the Christian "Shepherd of Hermes" (middle of the second century) is dependent upon an original form of the "Poimandres."[160] But his argument has not obtained any general consent. It is impossible to push the material of the Poimandres back into the first century--certainly impossible by any treatment of literary relationships. [158] J. Kroll, _Die Lehren des Hermes Trismegistos_, 1914, in _Beiträge zur Geschichte der Philosophie des Mittelalters_, xii. 2-4, pp. 388, 389. [159] Zielinski, "Hermes und die Hermetik," in _Archiv für Religionswissenschaft_, viii, 1905, p. 323. [160] Reitzenstein, _Poimandres_, 1904, pp. 10-13.