The Gospel of John bears indirect influences from Platonism, via earlier Jewish deuterocanonical texts, and may also have been influenced in less obvious ways by the cult of Dionysus, the Greek god of wine, though this possibility is still disputed.[16] Later Christian traditions about Jesus were probably influenced by Greco-Roman religion and mythology. Much of Jesus's traditional iconography is apparently derived from Mediterranean deities such as Hermes, Asclepius, Serapis, and Zeus and his traditional birthdate on 25 December, which was not declared as such until the fifth century, was at one point named a holiday in honor of the Roman sun god Sol Invictus. At around the same time Christianity was expanding in the second and third centuries, the Mithraic Cult was also flourishing.