From Religious Tolerance:
Many, perhaps most, Pagan religions in the Mediterranean area had a major seasonal day of religious celebration at or following the Spring Equinox. Cybele, the Phrygian fertility goddess, had a consort, Attis, who was believed to have been born via a virgin birth. Attis was believed to have died and been resurrected each year during the period MAR-22 to MAR-25.
Gerald L. Berry, author of “Religions of the World,” wrote:
“About 200 B.C. mystery cults began to appear in Rome just as they had earlier in Greece. Most notable was the Cybele cult centered on Vatican hill …Associated with the Cybele cult was that of her lover, Attis (the older Tammuz, Osiris, Dionysus, or Orpheus under a new name). He was a god of ever-reviving vegetation. Born of a virgin, he died and was reborn annually. The festival began as a day of blood on Black Friday and culminated after three days in a day of rejoicing over the resurrection.” 3
Wherever Christian worship of Jesus and Pagan worship of Attis were active in the same geographical area in ancient times, Christians:
“… used to celebrate the death and resurrection of Jesus on the same date; and pagans and Christians used to quarrel bitterly about which of their gods was the true prototype and which the imitation.”