Christianity hardly has a monopoly on the theme of resurrection, particularly around the winter holidays. A couple of thousand years ago, followers of a god named Mithras celebrated rebirth in much the same way as the followers of Jesus do today. Mithras was an early Roman god of the sun, who was born around the time of the winter solstice and then experienced a resurrection around the spring equinox. Sound familiar?
The cult of Mithras was a mystery religion, like that of Cybele and many other Roman Pagan beliefs. Author Ceisiwr Serith describes the cult's temples, or Mithraea, as being relatively small, and typically hidden underground. He also points out that it was only open to men, and very secretive, so it's unlikely that it was truly a big rival to the incoming Christian belief system.
In one legend, Mithras, who was popular amongst members of the Roman military, was ordered by the Sun to sacrifice a white bull. He reluctantly obeyed, but at the moment when his knife entered the creature's body, a miracle took place. The bull turned into the moon, and Mithras' cloak became the night sky. Where the bull's blood fell flowers grew, and stalks of grain sprouted from its tail. Mithras himself ascended to the light, and spent the rest of eternity hanging out with the Sun.
British author and poet Rudyard Kipling, who was fascinated by Mithraism, wrote Song to Mithras, which concludes as follows:
Mithras, God of the Midnight, here where the great bull dies,
Look on thy children in darkness. Oh take our sacrifice!
Many roads thou hast fashioned--all of them lead to the Light:
Mithras, also a soldier, teach us to die aright!
Ceisiwr Serith has a great essay on his website about why Christianity isn't stolen from the cult of Mithras, and it's one well worth reading. If you're interested in more about Mithras, check out his Mithraism Index.