Something to think about...

"Although many mystery cults vied for attention in the Roman world, perhaps the most important was Mithraism. Mithra was the chief agent of Ahuramazda, the supreme god of light in Persian Zoroastrianism. In the Roman world, Mithra came to be identified with the sun god and was known by his Roman title of the Unconquered Sun. Mithraism had spread rapidly in Rome and the western provinces by the second century A.D. and was especially favored by soldiers, who viewed Mithra as their patron deity. It was a religion for men only and featured an initiation ceremony in which devotees were baptized in the blood of a sacrificed bull. Mithraists paid homage to the sun on the first day of the week(Sunday), commemorated the sun's birthday around December 25, and celebrated ceremonial meals."

-taken from Western Civilization by Jackson J. Spielvogel