[ndigila]

Originally Posted by Muhammad_4

It says in the American Encyclopedia: The belief in the Oneness of God – as a theological movement – began at a very early stage in history, and in fact it preceded the belief in trinity by many decades. Christianity developed from Judaism, and Judaism firmly believes that there is one God. The path that led from Jerusalem (the home of the first disciples of Christ) to Nicea (where it was decided in 325 CE that Christ was equal to God in essence and eternal nature) can hardly be described as a straight path.
The doctrine of trinity which was affirmed in the fourth century CE bears no resemblance to the original teachings of Christ concerning the nature of God. Au contraire, it is the opposite, a deviation from that teaching. Hence it developed in opposition to the belief in One God… (27/294).

Muhammad, the ante-nicene church fathers affirmed the Trinity, here's some examples:
Athenagoras 175 A.D. Who, then, would not be astonished to hear men who speak of God the Father, and of God the Son, and of the Holy Spirit, and who declare both their power in union and their distinction in order, called atheists?

Clement of Alexandria 195 A.D. This visible appearance cheats death and the devil; for the wealth within, the beauty, is unseen by them. And they rave about the carcass, which they despise as weak, being blind to the wealth within; knowing not what a "treasure in an earthen vessel" 2 Corinthians 4:7 we bear, protected as it is by the power of God the Father, and the blood of God the Son, and the dew of the Holy Spirit.

Tertullian 212A.D. For the very Church itself is, properly and principally, the Spirit Himself, in whom is the Trinity of the One DivinityFather, Son, and Holy Spirit.

Hippolytus 205 A.D. Many other passages, or rather all of them, attest the truth. A man, therefore, even though he will it not, is compelled to acknowledge God the Father Almighty, and Christ Jesus the Son of God, who, being God, became man, to whom also the Father made all things subject, Himself excepted, and the Holy Spirit; and that these, therefore, are three.

Originally Posted by Muhammad_4

Despite the element of atheism in the words of Durant, which is something that he is known for, and which is apparent in his claim that the idea of eternal reward or punishment came from the Egyptians, tracing the origins of deviant idolatry in Christianity is no longer a secret, and he is not the only one who has researched them. In his book Christianity and Idolatry, Robertson states that Mithraism, which is a religion of Persian origin, flourished in Persia approximately six centuries before the birth of Christ, and it reached Rome around the year 70 CE, where it spread throughout the Roman lands. Then it reached Britain and spread to a number of British cities. What concerns us here about this religion is that it says:
- That Mithras, after whom it is named, was an intermediary between God and man (for a similar doctrine in Christianity, see Acts 4:12).
- He was born in a cave or in a corner of the earth (cf. Luke 2:8)
- His birthday was December 25 (which is the day celebrated by the Christians as the day when Jesus was born)
- He had twelve disciples (cf. Matthew 10:1)
- He died to save the world (cf. I Corinthians 15:3)
- He was buried but he came back to life (cf. I Corinthians 15:4)
- He ascended to heaven in front of his disciples (cf. Acts 1:9)
- He was called “Saviour” (cf. Titus 2:13)
- Among his attributes is that he is like a peaceful lamb (cf. John 1:29)
- The “Divine supper” was held in his memory every year (cf. I Corinthians 11:23-25)
- One of his symbols was baptism
- Sunday was sacred to them

When you separate the narratives from their ethics and significance, you could form any similarities. Apart from the 25th December celebration, all of the similarities you've mentioned above have been prophesied in the Old Testament and need not be borrowed from other religions.

By the way, you are yet to deal with the significance of the virgin birth in Islam, otherwise we could also claim it as Christian or Mithraic plagiarism.