Roman Empire and a devoted believer in Greco-Roman paganism, distrustful of Christianity as new and foreign. Thomas remarks that Celsus "is no genius as a philosopher". Nonetheless, most scholars, including Thomas, agree that Origen's quotations from The True Word reveal that the work was well-researched. Celsus demonstrates extensive knowledge of both the Old and New Testaments and of both Jewish and Christian history. Celsus was also closely familiar with the literary features of ancient polemics. Celsus seems to have read at least one work by one of the second-century Christian apologists, possibly Justin Martyr or Aristides of Athens. From this reading, Celsus seems to have known which kinds of arguments Christians would be most vulnerable to. He also mentions the Ophites and Simonians, two Gnostic sects that had almost completely vanished by Origen's time. One of Celsus's main sources for Books I–II of The True Word was an earlier anti-Christian polemic written by an unknown Jewish author, whom Origen refers to as the "Jew of Celsus". This Jewish source also provides well-researched criticism of Christianity and, although Celsus was also hostile to Judaism, he occasionally relies on this Jewish author's arguments. Work Celsus was the author of a work titled The True Word (Logos Alēthēs). The argument was contested by the contemporary Christian community and the book eventually banned in 448 AD by order of Valentinian III and Theodosius II, along with Porphyry's 15 books attacking the Christians, The Philosophy from Oracles, so no complete copies are extant, but it can be reconstructed from Origen's detailed account of it in his 8 volume refutation, which quotes Celsus extensively. Origen's work has survived and thereby preserved Celsus' work with it. Celsus seems to have been interested in Ancient Egyptian religion, and he seemed to know of Hellenistic Jewish logos-theology, both of which suggest The True Doctrine was composed in Alexandria. Origen indicates that Celsus was an Epicurean living under the Emperor Hadrian. Celsus writes that "there is an ancient doctrine [archaios logos] which has existed from the beginning, which has always been maintained by the wisest nations and cities and wise men". He leaves Jews and Moses out of those he cites (Egyptians, Syrians, Indians, Persians, Odrysians, Samothracians, Eleusinians, Hyperboreans, Galactophagoi, Druids, and Getae), and instead blames Moses for the corruption of the ancient religion: "the goatherds and shepherds who followed Moses as their leader were deluded by clumsy deceits into