Mithraism 

Considered to have been a Syrian offshoot of the ancient Persian Cult of Zoroaster.  It was introduced into the Roman Empire about 67 BC. (See The Hiram Key page 45)  It is said to have lasted until sometime during the 5th century in the Roman Empire.  It was never an 'official' Religion of the Roman Empire but was very popular among Roman soldiers and others. It is said to have involved a sacrificial meal where the blood of a bull was drunk and the flesh of the bull was eaten. (Anyone up for a piece of prime rib?)  Mithraism like Christianity practiced Theophagy (eating of one's God).

Mithraism had doctrines that included Baptism, a sacramental meal, belief in immortality and a savior God who died and rose again to act as a bargaining agent between god and man.  They also believed in a last judgment and in Heaven and Hell.

Their ceremonies used candles, incense and bells, just like Christianity which came many years later.  Did Christianity plagiarize Mithraism? 

Sounds real similar to Christianity.

Also, Mithra, like Jesus Christ and many others, is said to have been born from a virgin birth in a stable on 25 December about 600 BC.  Interesting day of the year as this is about the time of the winter solstice when the Sun (perhaps, Son) is reborn each year.  (Actually it seems that 25 December was the Winter Solstice at the time of the birth of Jesus Christ. The change in dates is probably due to the early quite inaccurate calendars.) Is Christianity just a modification of Sun Worship? 

It is said that Mithraism caused a bit of concern to the developers of the Christianity.  They solved this problem by saying that the devil went back in time to plant the ideas of Mithraism to make it look like the Christians just copied it. (If the devil, assuming that the devil really exists, can go back in time he must be godlike or at least a real good scientist.)