Here is a nifty quote from the New Schaff-Herzog Encyclopedia of Religious Knowledge (“Mithra, Mithraism,” VII, 419):
“The birth of Mithra and of Christ were celebrated on the same day; tradition placed the birth of both in a cave; both regarded Sunday as sacred; in both the central figure was a mediator (mesites) who was one of a triad or trinity; in both there was a sacrifice for the benefit of the race, and the purifying power of blood from the sacrifice was…a prime motive; regeneration or the second birth was a fundamental tenet in both…both had sacraments, in which baptism and a communion meal of bread and the cup were included; both had mysteries from which the lower orders of initiates were excluded; ascetic ideals were common to both; the ideas of man, the soul and its immortality, heaven and hell, the resurrection from the dead, judgment after death, the final conflagration by which the world is to be consumed, the final conquest of evil, were quite similar.”
Look for more such goodies in my forthcoming book, The Christ Myth Anthology. You’re first to hear of it!