There are certain important aspects of Christianity that are filled with the markings of paganism. For all we know paganism might actually have a wider influence on Christianity than we agree to admit.
Let’s take a look at some aspect of Christianity with pagan origins

1. The Word “Christianity”
The word 'Christian' was coined by Pagans.
The first followers of Christ borrowed Jewish terms to describe themselves and the two most popular names that they normally called themselves were "Disciples" and "Saints".

The word "Disciple" means one who is trained or taught, and appears 31 times in the book of Acts, starting with Acts 1:15.

The word "Saint" means set apart or separated, and appears 62 times in the New Testament, most commonly in the letters of Paul.

So how did the term Christianity originate from?

Two of the early missionaries, Paul and Barnabas, went to work spreading the Gospel in the Pagan metropolis of Antioch, where the locals derisively called them 'Christians'.
Acts 11:25-26 - “Then departed Barnabas to Tarsus, for to seek Saul, and when he had found him, he brought him unto Antioch. And it came to pass, that a whole year they assembled themselves with the church, and taught much people. And the disciples were called Christians first in Antioch”

Paul and Barnabas would certainly not dispute that they were indeed Christians and would have been quite pleased that the Romans made it the official name.

2. Easter

Easter is without doubt, the most significant event on the Christian calendar. It is the time Christians remember the death and resurrection of Jesus Christ.

But did the celebration of Easter start with Christians?

The early Christians called their celebration Paschal, from the Hebrew word for the Passover feast, pesach.

However, plenty of people were already celebrating a feast in the month of April called Eostur-monath, which means, literally, “month of Eostur.” Eostur, also spelled Eostre or Ostara, was the Anglo-Saxon goddess of fertility.

Early in the history of Christianity, many pagan observances were adapted for the new faith. The early missionaries discovered that it was easier to get converts to celebrate a new name than it was a new date.

3. Amen

Amen, the very last word in the Bible (Rev 22:21), could well have begun as a Pagan word. Yet Christians end their prayers, Scripture readings, and hymns by saying Amen as an expression of concurrence. They also say it to acknowledge their agreement or reinforce a statement that another person has said.

The root of the word comes from Hebrew aman, which means to nourish and make strong. Emunah (faithfulness) also comes from aman. The ancient Greeks used the word (AMHN) from Hebrew to mean 'truth', 'surely', 'absolutely'

From old Egyptian texts, people regarded the sun as the emblem of the Creator. They called the sun Ra, and all other gods and goddesses were forms of the Creator. One of these gods was Amen; a secret, hidden and mysterious god named variously Amen, Amon, Amun, Ammon and Amounra. Amen was elevated from being a minor god to be the national god. This position gave Amen the attributes and characteristics of the most ancient gods, and his name became Amen-Ra, that is, a supreme form of God the Creator.

Jews settled in Egypt for around 400 years and during this sojourn they would certainly have been fully exposed to the worship of Amen-Ra. By the time of their exodus from Egypt, the term 'Amen' would be in their language even if it was not their god. It would be a word that had associations with reverence and majesty.

Amen was seen as a powerful god and the name continued, out of context, as an exclamation or salutation.
In the Bible (Rev 3:14) we see Jesus Christ referred to as "The Amen". Thereby the name used for an old Egyptian god is replaced by the same name used for Christ.

4. Eucharist

I guess you know about the Christian Eucharist, right?—the Lord's Supper. It commemorates the supper Jesus had with his disciples the night before the Romans nabbed Him and dragged him off, eventually to be crucified. Right? Christians still reenact that meal with Jesus, the meal with the God Jesus. You know this. Some Christians believe the meal is the body and blood of Jesus.

What you maybe didn't know is that Mithras' faithful celebrated a sacred meal with their God. So did followers of Adonis, Attis, Osiris, and other Pagan Gods of the Mystery Religions. New members of the Mysteries of Isis and Osiris completed their initiation with a sacramental meal.

The notion that worshipers eating together would be joined by their God was widely diffused throughout the ancient world hundreds of years before Jesus. In Rome the rite even had its own name, "lectisternia." A lectisternia was a sacred meal in which an icon of the God was actually brought to the table with the celebrants. In Rome the whole Senate celebrated a sacred meal, with a statue of Jupiter lying on a cushion, and the two goddess Juno and Minerva in chairs beside him

5. Baptism

By the time of Jesus purification with water was already an ancient Pagan sacrament. Purification—from unclean foods, or acts, or contacts—is an idea so old it fades into pre-history. Pagans purified themselves with fire, incense, blood sacrifice; they even purified themselves with a winnowing fan or sea onions! But the most used, most widespread tool of pagan purification was...water

Pagan water purification rituals were used in the archaic Near East and are written about in the Old Testament.
Homer mentions the washing of hands before prayer, and the purification of an entire army with water [Iliad, 1.313].

The Greeks even had priests, kathartai, who specialized in purification with water. After the conspiracy of Cylon in Athens in 632 BC, a fellow named Epimenides of Crete purified the entire city -- with water [Diogines Laertius 1.10.3]. Mithra's followers celebrated the sacrament of taurobolium—baptism in the blood of a bull, with the result of "Salvation". Pagans at Gerasa celebrated the Maioumas, rites in which women bathed and were purified in a sacred pool outside town.

New members into the Mysteries of Isis / Osiris began their initiation with a sprinkling of purifying waters brought from the Nile. The result of the baptism and initiation? Salvation

6. Christmas

By now you should already know that Jesus Christ was not born on the 25th of December. If so, why celebrate Christmas on that particular day.

The earliest history of Christmas is composed of "pagan" (non-Christian) fertility rites and practices which predate Jesus by centuries. The truth is, in short, the real history of Christmas has nothing to do with Christianity.

Saturnalia was a festival held between 17 and 24 December, which began in the days of the Roman Empire. This was a week of feasting, gift-giving and an excuse for an orgy during the Northern Hemisphere's winter solstice. The objective of the debauchery and dancing around was to give the sun a nudge and send a message to Mother Earth to begin reproducing for the spring. This seemed to work quite well because sure enough, in spring things started growing again.

Celebrating the winter solstice was forbidden by the early church, but customs survived anyway and it didn't take much to tempt Christians to join in the solstice feast in honour of the Pagan god Mithra. So the church provided an alternative with a festival in honour of the birth of Christ and celebrations were definitely in order.

In the 2nd century, the winter solstice was 6 January and Christians celebrated both the birth and the appearance of God's Son on that day, Epiphany Day.

By the 4th century, the date for the winter solstice was moved to 25 December and Pope Julius I declared that Jesus' birthday celebrations would also be on that day. This effectively transformed the Pagan occasion into a Christian holy day (holiday).

7. The cross

You probably already know that the cross is used within the Christian faith and among the Christian sects. It is the most common symbol seen in, on, and around Christian churches all over the world.

This has not always been the case however. Christians didn’t use the sign of the cross as their religious symbol for many generations after Christ was crucified. Rather than being a Christian symbol of hope and love, it only had the negative association as an execution apparatus for criminals.

The cross is a pagan symbol that was adored in Egypt thousands of years before Jesus was born. The Roman Catholic Church adopted the cross symbol at least 600 years after Jesus was supposedly crucified.
There are several pre-Christian beginnings of the cross symbol that can be found. These crosses range in design but are a cross nonetheless.

In Babylon the cross took its place with a crescent moon and was the symbol of their moon deity.
In Egypt the ankh cross (a Tau cross topped by an inverted tear shape) reflects their Goddess of Truth. It also represents Isis and Osiris and their sexual union.

In India, in Hinduism, the upright shaft stands for the higher states of being while the horizontal bar stands for the lower states of being.

In Assyria the corners of the cross represent the four directions in which the sun shines.
In Scandinavia the Tau cross symbolized the hammer of the God Thor. In Europe the use of a human effigy on the cross in a scarecrow form has been used since ancient times

Whether Jesus was actually crucified on a cross or a pole is an argument for another day, but using a cross to represent the death of Christ is definitely of pagan origin.

8. Virgin Mary

What do you know about Mary, Mother of Jesus Christ? You probably remember a Virgin Mary, who conceived a God. But is the idea of a mortal virgin mother giving birth to a God new? Not really.

There are at least a few dozen instances of virgin births in history, mostly of religious figures.

Eighteen hundred years before Christ, we find carved on one of the walls of the great temple of Luxor a picture of the annunciation, conception and birth of King Amunothph III, an almost exact copy of the annunciation, conception and birth of the Christian God.

Krishna was born of the virgin Devaki. Savior Dionysus was born of the virgin Semele. Buddha too was born of a virgin, The old Teutonic goddess Hertha was a virgin impregnated by the heavenly Spirit and bore a son. Scandinavian Frigga was impregnated by the All-Father Odin and bore Balder, the healer and savior of mankind.

In Phrygia, Attis was born of the virgin Nama. In Egypt, virgin mother Isis begat Horus. A Roman savior Quirrnus was born of a virgin.

Even images of a loving mother with her child which is also a picture that seems to be familiar with Christians did not even start with Christianity.

9. Christ savior

Not only the idea of a savoir born of a virgin mother, who was to die and resurrect on the third day originate with Christianity, but all the other miraculous events, such as the stable cradle, the guiding star, the massacre of the children, the flight to Egypt, and the resurrection and bodily ascension toward the clouds, have not only been borrowed, but are even scarcely altered in the New Testament story of Jesus.

Dionysus is said to have descended to the underworld and conquered death, ultimately bringing his dead mother back to the land of the living. He also is said to have died and been raised again. His followers called him Lysios or Redeemer, and grape juice commonly was used to symbolize his blood.

Like Jesus, Dionysus is a god whose tragic passion is re-enacted by eating his flesh and drinking his blood”.
The Dionysus cult reached Rome in 496 B.C., but had been around long before that.

Osiris-Dionysus is God made flesh, the savior and “Son of God.” His father is God and his mother is a mortal virgin. He is born in a cave or humble cowshed on December 25 before three shepherds. He offers his followers the chance to be born again through the rites of baptism. He miraculously turns water into wine at a marriage ceremony.

He rides triumphantly into town on a donkey while people wave palm leaves to honor him. He dies at Eastertime as a sacrifice for the sins of the world. After his death he descends to hell, then on the third day he rises from the dead and ascends to heaven in glory. His followers await his return as the judge during the Last Days. His death and resurrection are celebrated by a ritual meal of bread and wine, which symbolize his body and blood.

Prometheus is another legendary, mythological god who experienced a death similar to that of Christ. His story first circulated around 547 B.C.
Or, consider Krishna, the ancient Hindu deity who is alleged to have shared a doom similar to Christ’s. He has been portrayed as hanging on a cross, with holes through his hands and his feet. His title?—“Our Lord and Savior.” Krishna supposedly “rose from the dead” and then “ascended bodily into heaven”. He even is purported to have said: “Do good for its own sake, and expect not your reward for it on Earth”. Christ employed the same idea in Matthew 6. But Krishna’s story dates to 1200 B.C.

In the Egyptian Papyrus of Ani (also known as The Egyptian Book of the Dead), which is dated between 1450 and 1400 B.C., the god Osiris commands the titles of King of Kings, Lord of Lords, and Prince of Princes. “Osiris, the Egyptian Saviour, after being put to death, rose from the dead, and bore the title of ‘The Resurrected One’ ” (p. 221, emp. in orig.).

In the latter part of the papyrus, a specific creed is provided that supposedly is capable of providing justification for the person who recites it upon his or her entrance into eternity. That creed reads as follows: “I have given bread to the hungry man, and water to him that was athirst, and apparel to the naked man, and a ferry-boat to him that had no boat”. The writer of this papyrus could have copied the words of Jesus as found in Matthew 25:31-46—except for one small fact: the Papyrus of Ani dates to 1400 B.C.—over a thousand years before Christ made His earthly appearance.

Furthermore, in 550 B.C., Confucius said: “Do not to another what you would not want done to yourself.” Christ uttered an almost identical statement approximately 600 years after Confucius when He said: “And as ye would that men should do to you, do ye also to them likewise” (Luke 6:31).

The Sumerian goddess Inanna, or Ishtar, was hung naked on a stake, and was subsequently resurrected and ascended from the underworld. One of the oldest resurrection myths is Egyptian Horus. Born on 25 December, Horus and his damaged eye became symbols of life and rebirth. Mithras was born on what we now call Christmas day, and his followers celebrated the spring equinox.

http://giftedgreen.com/content/?q=9-Aspects-Of-Christainity-With-Pagan-Origins