The faithful referred to Mithras as "the Light of the World", symbol of truth, justice, and loyalty. He was mediator between heaven and earth and was a member of a Holy Trinity. The worshippers of Mithras held strong beliefs in a celestial heaven and an infernal hell. They believed that the benevolent powers of the god would sympathize with their suffering and grant them the final justice of immortality and eternal salvation in the world to come. They looked forward to a final day of judgment in which the dead would resurrect, and to a final conflict that would destroy the existing order of all things to bring about the triumph of light over darkness. Purification through a ritualistic baptism was required of the faithful, who also took part in a ceremony in which they drank wine and ate bread to symbolize the body and blood of the god. Sundays were held sacred, and the birth of the god was celebrated annually on December the 25th. After the earthly mission of this god had been accomplished, he took part in a Last Supper with his companions before ascending to heaven, to forever protect the faithful from above. However, it would be a vast oversimplification to suggest that Mithraism was the single forerunner of early Christianity. Aside from Christ and Mithras, there were plenty of other deities (such as Osiris, Tammuz, Adonis, Balder, Attis, and Dionysus) said to have died and resurrected. Many classical heroic figures, such as Hercules, Perseus, and Theseus, were said to have been born through the union of a virgin mother and divine father. Virtually every pagan religious practice and festivity that couldn't be suppressed or driven underground was eventually incorporated into the rites of Christianity as it spread across Europe and throughout the world
http://www.iranvision.com/mithras.html

It is very plossible that the cult of Mithras influenced early christians. Despite the fact that Mithras was an Iranian god amongst many, he became very popular amongst the Romans who spread its faith and was a major cult figure to the soldiers as the eternal peace he offered was attained by those who died heroically. So its likely some aspects and celebrations were picked up and a connection made by early christians to spread their faith. After all just about every fun thing we know about in christianity started off as a pagan celebration or ritual. Hell even the birth day cake is based on a Greek celebration. Origianlly once a year "on the birthday of the city of Athens" the priests of Athena would take a cake into the parthenon with candles on it. If the priests could blow out all the candles at once than Athena would grant their wish. "good harvest usually". This spread to the households. birthdays of individuals were than celebrated this way with the blowing out of candles and a wish to Athena. This just spread and most forgot who they were makeing the wish to.

now more on subject is Easter, even the name comes from Eastre goddess of spring and rebirth. On this day Her son Aden "a kind and loving healer of the people" would resurrect only to die again come winter and resurrect the next year in spring. The Easter bunny is based on Eastre's sacred animal the rabbit. and the hideing of eggs comes from the ritual burying of eggs with painted symbols of them as the egg is the symbol of life and the eggs were meant as sacrifices "in other words you're not supposed to eat them or let them hatch so you're sacrificing the eggs."
and I could go on and on like this for even every day things we never pay any attention to.

you may reject the old ways but your still doing the rituals the gods taught you so maybe they don't care in whose name your doing it so long as your doing it.

And we haven't even touched the extraordinary similar parallels between Buddhism and Christianity either.