One of the arguments used by anti-Christians to discredit the historicity of Christ, His atonement for sin and Christianity as a whole is that Jesus was “modelled” after older pagan deities like the Roman Mithras or the Greek Zeus.
One of them quoted Gerald Berry’s Religions of the World, saying:
“Both Mithras and Christ were described as ‘the Way, ‘the Truth,’ ‘the Light,’ ‘the Life,’ ‘the Word,’ ‘the Son of God,’ ‘the Good Shepherd.’ The Christian litany to Jesus could easily be an allegorical litany to the sun-god. Mithras is often represented as carrying a lamb on his shoulders, just as Jesus is. Midnight services were found in both religions. The virgin mother… was easily merged with the virgin mother Mary. Petra, the sacred rock of Mithraism, became Peter, the foundation of the Christian Church.”
These critics also allege that Mithras was born on December 25; was visited by shepherds at birth; had 12 apostles, instituted a last supper and died for humanity – all of which the New Testament allegedly adopted for Jesus.
First, we all need to understand the historical setting of the Roman Empire where Christianity and Mithraism thrived. The early church consistently refused to integrate with the surrounding syncretic religions. This was why for three centuries, Christianity was despised and persecuted.
In first century Roman Empire, four major classes of religions were embraced:
Nature religions – revolving around belief in supernatural power in natural things and worship of trees, sun, moon, rivers, stones and deities in charge of them e.g Greek paganism.
State religion – the Emperors were believed to be gods and accorded divine honours. Festivals were held in their honour and sacrifices offered to their images for the unity of the Empire.
Mystery religions – secret societies or cults that claim to help people out of difficult life situations and provide a bridge to the afterlife. They had certain ceremonial acts such as water rites, ritual meals, blood sacrifices which were kept secret to non-initiates e.g. Mithraism, Eleusinian mysteries, Bacchanalian mysteries, mysteries of Isis.
Judaism – the early Romans couldn’t initially distinguish Jews who practiced Judaism from Christian Jews. In Acts 18:12-17, Gallio the Roman governor, dismissed Paul’s case as a dispute within the sects of Judaism. But as unbelieving Jews increasingly opposed Christianity, the heathen also joined them. 
What impressed the pagan world of the new faith of Christianity was not its familiarity but its difference. Christianity was regarded a “strange religion;” an illegal religion (religio illicita), and this led to the murder of many Christians.
If Jesus was a myth and Christianity was merely an offspring of paganism, the disciples and early Christians wouldn’t have laid down their lives instead of giving it up.
The pagans who killed and persecuted Christians during those times knew full well that what they believed was far different from what their victims believed.
Mithraism was a mystery religion practiced between 1st-4th century A.D. The religion had its roots in the Hindu Vedas. It developed in Persia about 500 years before Christ and further developed in Zoroaster’s (Zarathustra) movement about 200 years before Christ.
Mithraism reached its peak in third century Rome, during the same period Christianity was rapidly growing.
Those who claim Mithras was a prototype of Christ assume that Mithra worship was a cohesive, consistent and monolithic religion, but this is not so:
“The god is unique in being worshipped in four distinct religions: Hinduism (as Mitra), in Iranian Zoroastrianism and Manicheanism (as Mithra), and in the Roman Empire (as Mithras).” 
Not only were there variations in his name, each religion’s beliefs about Mithra also differed. The Persian cult differs markedly from the Roman one. The Roman Mithras is said to have slain a bull but there is no evidence that the Persian Mithra ever had anything to do with killing a bull.
Some writers agree that the bull-slaying Mithras must have been a god worshipped in the 1st century BC to whom an old name was applied. 
This eliminates any possibility of someone modelling Christ after Mithras.
Many critics also ignorantly conflate Mithra with Sol when they identify him as the sun god.
Various artworks depict Mithras dining with Sol; Mithras ascending behind Sol in the latter’s chariot and both deities shaking hands and at an altar with pieces of meat on a spit. One artwork shows Sol kneeling before Mithras who holds an object resembling a bull’s haunch. 
This difference is crucial, because the birthday of Sol Invictus was December 25, but that was not Mithras’ birthday. Amongst Roman mystery cults, Mithraism had no “public” face; its ceremonies were confined only to the initiates. The festival of Sol Invictus on December 25 wasn’t specific to Mithraism. 
Mithras wasn’t born of a virgin like Jesus. He was said to have been miraculously born from a rock and there are different accounts of this. One version said he leaped out of the rock as a child, another says as a youth, another says as flames yet another said he emerged as thunderbolt. But there is no account of Mithras born by a virgin mother.
The claim of Mithras visited by shepherds at birth or having 12 apostles lacks documented evidence. This is simply a cheap attempt by hostile critics to “christianize” the myths of Mithras and create a false parallel with Christ. A scholar admits:
“We possess virtually no theological statements either by Mithraists themselves or by other writers.” 
The alleged salvific death of Mithra is based on an inscription that says “and you have saved us … in the shed blood.” But no written narrative or theology from Mithraism survives and limited information can be derived from these inscriptions. “However, in the absence of any ancient explanations of its meaning, Mithra’s iconography has proven to be exceptionally difficult to decipher.” 
According to Robert Turcan, Mithraic salvation had little to do with the other worldly destiny of individual souls, but was based on the Zoroastrian pattern of man’s participation in the cosmic struggle of the good creation against the forces of evil. That is far from what the New Testament teaches.
The so-called “last supper” by Mithras is a fanciful deduction from the ritual meal observed by Mithraists. Modern critics, deploying a twisted logic, assume that since Mithraism had such ritual meals and was supposedly older, Christianity must have stolen the idea from them! This hypothesis falls flat on its face.
Most of the textual evidence for Mithraist doctrine dates after the New Testament was widely circulated. There is even the possibility that Mithraism adopted the communion rite from Christianity, because they had no concept of death and resurrection of their god.
Justin Martyr, in his First Apology (chapter 66) accused the Mithraists of diabolically imitating the Christian communion.
David Ulansey therefore concludes: “Owing to the cult’s secrecy, we possess almost no literary evidence about the beliefs of Mithraism. The few texts that do refer to the cult come not from Mithraic devotees themselves, but rather from outsiders such as early Church fathers, who mentioned Mithraism in order to attack it, and Platonic philosophers, who attempted to find support in Mithraic symbolism for their own philosophical ideas.” 
In light of the post-Christian origins of the mysteries of Mithras, Dr. Edwin Yamauchi states: “Those who seek to adduce Mithra as a prototype of the risen Christ ignore the late date for the expansion of Mithraism to the west.” 
Zeus and Jesus
Some uninformed critics and misguided Christians assert that Jesus was modelled after Zeus by some crypto-pagans in the early church who stripped Christianity of its Hebrew roots and changed the Saviour’s name into a pagan god’s so as to merge it with paganism.
A. B. Triana wrote in Origins of Christianity:
“They (the Graeco-Roman World) had worshiped Zeus as the supreme deity. Their savior was Zeus, so now they were ready to accept Jehoshua as Jesus – Ieosus, meaning hail Zeus. Now our translated scriptures say that Jahwah’s (Jehovah’s) Son’s name is Jesus, which is a compound word made up of Ie and Zeus (Hail Zeus)”
Proponents of this bizarre conspiracy theory (mostly Hebrew Roots adherents) are not only bereft of proofs, but also stumped by their own imaginations.
They teach that anyone who uses the name of Jesus instead of His Hebrew name, Yahshua, is worshipping a false god and is not saved. Actually, the Hebrew name of Jesus is Yeshua, a form of the name Joshua and both mean the same: “Yahweh is salvation.”
The similarity in pronunciation between Ieosus and Zeus doesn’t imply a borrowing of one from the other. To suggest that the name Bruno was derived from Juno is a phonetic fallacy. The Greek word for “hail” is xaipe or xaipete and it’s not a constituent of the Greek name Ieosus, so the “hail Zeus” accusation is hinged on wholesale ignorance.
Ieosus is the Greek name of Christ and that was the language in which the New Testament was written. First century works of Jewish historian, Josephus Flavius – written in Koine Greek – refer to at least 20 different people with the name Jesus (i.e Ieosus).  The Hebrew name of Jesus is not “too sacred” to be transliterated into another language neither does its translation change its meaning.
God’s name is not limited by human language; He created all languages and may not expect everyone to use the same name for Him. The name of Jesus given in Matthew 1:21 is the one by which men shall be saved from their sins. This name carries the same power and authority whether as Iesus (Latin), Yasu (Arabic), Jésus (French) or Jesu (Yoruba, Igbo).
The name “Jesus” is the Anglicized form of Ieosus or Yeshua and it has nothing to do with Zeus. No informed person with a modicum of intellectual honesty would claim Jesus is a copy of Zeus.
Zeus’ infancy narrative even has varying accounts. One version says he was raised by Gaia; another says by a goat named Amalthea; another says by a nymph Adamanthea; another says a nymph named Cynosura, yet another says by a shepherd family.
Some critics have also attempted to forge a link between Christ and Dionysus, the Greek god of wine, ritual madness, fertility and religious ecstasy. The mysteries of Dionysus was known as a ‘cult of souls’ in which priests forged necromantic links with the dead. But the Lord Jesus “has destroyed death and has brought life and immortality to light through the gospel” (2 Tim. 1:10).
Jesus Christ is the fulfillment of the Law and Prophets of the Old Testament. He has no link to any ancient pagan deity neither was Christianity built on the foundation of myths artfully spurn by pagans.
1. Titilayo Dipe, History and Doctrines of the Early Church, University of Ibadan Press, 1992, 2-4.
2. John Hinnells, Studies in Mithraism, Rome, 1990, 11.
3. David Ulansey, Origins of the Mithraic Mysteries, Oxford University Press, 1991, 8.
4. Roger Beck, Mithraism, Ashgate Publishing, 2004, 287-287.
5. Walter Burkert, Ancient Mystery Cults, Harvard University, 1987, 10.
6. Clauss Manfred, The Roman Cult of Mithras: The God and his Mysteries, Richard Gordon Books, 2001, xxi.
7. David Ulansey, p. 8.
8. David Ulansey, The Cosmic Mysteries of Mithras.
9. M. J. Vermaseren, Mithras, The Secret God, Chatto and Windos, 1963, 76.
10. Paul Eddy and Gregory Boyd, The Jesus Legend: A Case for the Historical Reliability of the Synoptic Jesus Tradition, Baker pub., 2007, 129.