Christianity is based on the unique belief that Jesus was God's Son, born of a virgin, sacrificed for the Salvation of man. In reality, as sacrificed virgin-born Savior Son of God, Jesus was not unique. Not even close.
The Jesus myth simply followed the traditional model of the ancient pagan savior-gods.
At the time of Jesus of Nazareth, as for centuries before, the Mediterranean world roiled with a happy diversity of creeds and rituals. Details varied according to location and culture, but the general outlines of these faiths were astonishingly similar. Roughly speaking the ancients' gods:

Were born on or very near our Christmas Day

Were born of a Virgin-Mother

Were born in a Cave or Underground Chamber

Led a life of toil for Mankind

Were called by the names of Light-bringer, Healer, Mediator, Savior, Deliverer

Were however vanquished by the Powers of Darkness

And descended into Hell or the Underworld

Rose again from the dead, and became the pioneers of mankind to the Heavenly world

Founded Communions of Saints, and Churches into which disciples were received by Baptism

Were commemorated by Eucharistic meals.

Krishna was born of the virgin Devaki; the Savior Dionysus was born of the virgin Semele. Buddha too was born of a virgin, as were the Egyptian Horus and Osiris. 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.

Mithras was born in a cave, on December 25th, of a virgin mother. He came from heaven to be born as a man, to redeem men from their sin. He was know as "Savior," "Son of God," "Redeemer," and "Lamb of God." With twelve disciples he traveled far and wide as a teacher and illuminator of men. He was buried in a tomb from which he rose again from the dead -- an event celebrated yearly with much rejoicing. His followers kept the Sabbath holy, holding sacramental feasts in remembrance of Him. The sacred meal of bread and water, or bread and wine, was symbolic of the body and blood of the sacred bull.

The celebration of Christmas on December 25 was originally the pagan birthday of Mithras, the sun god, whose day of the week is still known as "Sunday." The halo of light which is usually shown surrounding the face of Jesus and Christian saints, is another concept taken from the sun god. The theme of temptation by a devil-like creature was also found in pagan mythology. In particular, the story of Jesus's temptation by Satan resembles the temptation of Osiris by the devil-god Set in Egyptian mythology.

So why is there a thing known as Christianity?

More than likely because of one man, more than any other. His was known by the name Constantine, He was a Roman Emperor and He invented Roman Catholicism.
In 325 C.E. the Roman Emperor Constantine I, convened what is now called the ‘Nicene Council’..  Gathering 300 elder/Bishops together, in order to unify basic doctrines, and establish common practices.
(Constantine knew that that religion would play a Important role in Unifying his kingdom, but first he had to unify Religion in order to unify his kingdom.)

One of the most OVER LOOKED FACTS about this Council is this: This * universalizing * produced the *ROMAN CATHOLIC CHURCH *.

The Latin word *CATHOLIC *
means * UNIVERSAL *.,and there was NO Catholic on this planet prior to this Council.

(Constantine held the pagan title * Pontifex Maximus* as head and protector of the Pagan Worship and later Popes of the Roman Catholic Church took this title for themselves.)  It can be safely stated that Constantine himself was a worshiper of Mithras and Sol Deus Invictus.  Would it not be possible to gather all the different nationalities around his altars? Could not Sol Deus Invictus, to whom even Constantine dedicated his coins for a Long time, or Sol Mithras Deus Invictus, venerated by Diocletian and Galerius, become the supreme god of the empire?  Constantine may have pondered over this. Nor had he absolutely rejected the thought even after a miraculous event had strongly influenced him in favour of the God of the so-called Christians.

Eusebius (Vita Const., I, xxvi-xxxi). (As the story goes)  He saw, according to the one in a dream, according to the other in a vision, a heavenly manifestation, a brilliant light in which he believed he descried the cross or the monogram of Christ. Strengthened by this apparition, he advanced courageously to battle, defeated his rival and won the supreme power. It was the result that gave to this vision its full importance, for when the emperor afterwards reflected on the event it was clear to him that the cross bore the inscription: HOC VINCES (in this sign wilt thou conquer).

A monogram combining the first letters, X and P, of the name of Christ (CHRISTOS), a form that cannot be proved to have been used by Christians before, was made one of the tokens of the standard and placed upon the Labarum (q. v.). In addition, this ensign was placed in the hand of a statue of the emperor at Rome, the pedestal of which bore the inscription:

"By the aid of this salutary token of strength I have freed my city from the yoke of
tyranny and restored to the Roman Senate and People the ancient splendour and glory."  Directly after his victory Constantine granted tolerance to the so-called Christians and next year (313) took a further step in their favour.  In 313 Licinius and he issued at Milan the famous joint edict of tolerance.

For a time it seemed as if merely tolerance and equality were to prevail. Constantine showed equal favour to both religious. As pontifex maximus he watched over the heathen worship and protected its rights.  It is true that the believers in Mithras also observed Sunday as well as Christmas. (long before the Catholic's did) Constantine moreover placed Sunday under the protection of the State. Consequently Constantine speaks not of the day of the Lord, but of the everlasting day of the sun.  According to Eusebius, the Sun worshipers also were obliged on this day to go out into the open
country and together raise their hands and repeat the prayer already mentioned, a prayer without any marked Christian character (Vita Const., IV, xx)


* Nicene Council*(that’s to say) was the blending of all these pagan sects into one UNIVERSAL/Catholic religion with all their holey days, their rituals, and doctrines.