History
In the centuries before 1 AD, many stories circulated about a male entity that was part god and part human. These entities are often referred to as godmen. The stories of these godmen were somewhat consistent from religion to religion. In Alexandria, Egypt, he was Aion; in Asia Minor, Attis; in Babylonia, Antiochus; in Egypt, Osiris; in Greece, Dionysus; in Syria, Adonis; in Rome, Bacchus; in Persia, Mithras.
Pagan spirituality of the Osiris-Dionysus sects was composed of two components. The Outer Mysteries consisted of Pagan beliefs and practices that were widely disseminated and taught to the general public. The Inner Mysteries were revealed only to those who had been initiated into the Pagan religions. The initiates learned that Osiris-Dionysus was not a historical person. His legends were simply fables containing spiritual and moral teachings.
Final Comments
The Pagan godman stories had been circulating for centuries before the birth of Christ. Obviously if any copying occurred, it was the followers of Jesus Christ incorporating the stories of Osiris-Dionysus, not vice-versa.
Also note that Osiris-Dionysus shows *very few* similarities to the Jewish Messiah.