Ancient legend ...

... says that on December 25th, Mithras was conceived in the shade of a sacred tree beside a sacred stream, holding a knife and a torch. A raven from the sun god Sol then gave him a message that told him to slay the mysterious white bull.
Mithras obeyed and tracked down the bull, accompanied by two minor deities, Cautes and Cautophes. When he finally met up with the mystic bull, he did slay it, using the knife he was born with. The white bull then became the moon and Mithras’ vicorious cape became the sky. Supposedly, this evolved into the alteration of night and day.
Animals and plants were formed, and seasons developed and began to change. Time was developed and the scene for mankind was now set. The legend ends with Mithras’ climbing into Sol’s golden chariot and flashing across the sky in glory.