Some of your facts are wrong.
The earliest known Christian writings were the letters of Paul, written around the year 50.
But you are right here.
I think it is great that you admit that a man named Paul wrote the letters of Paul. For a long time, liberal critics would not admit this, but with so many of the early Church fathers quoting Paul, there would have to have been widely circulated letters at least 20 to 40 years prior to AD 90. So I agree. The letters of Paul were written from the early 50s to the mid 60s.
The Gospels existed in oral form until the same time period. The Bible was written by the eyewitnesses of Jesus' ministry His own disciples and by apostles that later arose in the first century church, Paul, Luke, Mark, James and Jude. Although 19th century scholars once tried to assign later dates to New Testament books, modern scholars regard the New Testament as a primary source document from the first century. There are many ways to validate the Bible's authenticity.
Eusebius, the 4th century historian, drawing information from Papias, who was the Apostle John's student, tells us that the Gospel of Mark was actually Peter's account of the life of Jesus as told to his student Mark:
"The Elder (John) used to say this also: 'Mark, having been the interpreter of Peter, wrote down everything that he mentioned, whether sayings or doings of Christ, not, however, in order. For he was neither a hearer nor a companion of the Lord; but afterwards, as I said, he accompanied Peter, who adapted his teachings as necessity required ... So then Mark made no mistake, writing down in this way some things as he (Peter) mentioned them; for he paid attention to this one thing, not to omit anything that he had heard, not to include any false statement among them."
Eusebius also tells us that Mark was Peter's interpreter and travelled with him to Rome in 60 A.D. During the reign of the Roman emperor Nero, the Roman authorities used a copy of Mark's Gospel as evidence to implicate the Christians as the cause of a large fire which had burned much of the city. On a papyrus scroll appeared the title: "The Gospel of Jesus Christ the Son of God." In the ensuing period, Christians were persecuted as scapegoats. Evidently the title of Mark's Gospel was misconstrued as treasonous.
Paul was, in fact, a gnostic. He knew there was no Jesus.
Gnostic views of the Godhead were opposed by Paul in his writings, by Peter in his second epistle, by the Apostle John in his writings, and by the Church Fathers and apologists.
The Apostle Paul wrote in his first epistle to Timothy:
"O Timothy, keep that which is committed to thy trust, avoiding profane and vain babblings, and oppositions of science falsely so called" (1 Timothy 6:20).
It's worth noting here that the word translated as "science," or as "knowledge" in some translations, is the Greek word gnosis. Paul is warning his young disciple Timothy against the error of Gnosticism. Likewise, the letter to the Colossians also deals with Gnosticism.
"Beware lest any man spoil you through philosophy and vain deceit, after the tradition of men, after the rudiments of the world, and not after Christ "(Colossians 2:8 ) .
"Let no man beguile you of your reward in a voluntary humility and worshipping of angels, intruding into those things which he hath not seen, vainly puffed up by his fleshly mind" (Colossians 2:18 ) .
Peter's second epistle also warns against heresies. Many scholars believe he is referring specifically to the teachings of Gnosticism.
"But there were false prophets also among the people, even as there shall be false teachers among you, who privily shall bring in damnable heresies, even denying the Lord that bought them, and bring upon themselves swift destruction" (2 Peter 2:1).
John's writings were written in part to counter the Gnostic error that supposed that Christ came in spirit form only, but not in human flesh.
"That which was from the beginning, which we have heard, which we have seen with our eyes, which we have looked upon and touched with our hands" (1 John 1:1).
"By this you know the Spirit of God: every spirit which confesses that Jesus Christ has come in the flesh is of God" (1 John 4:2) .
John further condemns the "mystery religions" that had corrupted first century Jews represented by the harlot in the book of Revelation.
"And the woman was arrayed in purple and scarlet colour, and decked with gold and precious stones and pearls, having a golden cup in her hand full of abominations and filthiness of her fornication: And upon her forehead was a name written, MYSTERY, BABYLON THE GREAT, THE MOTHER OF HARLOTS" (Revelation 17:3,4) .
Nero was emperor from 54-68. Christians believe Jesus died between the years 30 and 35. In any case, there were no literalist Christians at the time of Nero. Literalist Christianity didn't get started until sometime after the Maccabee rebellion in 70.
The Maccabean Rebellion occurred at the time of 165 BC not 70 AD.
You may be thinking of the seige of Jerusalem by Titus from 68 to 70 AD.
Besides, even if they did believe that Jesus really did exist and really was the son of God, that doesn't mean they were right. I never said the New Testament was wrong about every single thing contained in its pages. I said that it's uncorroborated with respect to Jesus. The fact that certain things it contains have been corroborated is irrelevant. In other words, just because parts of it are true doesn't mean all of it is.
You may not believe it, but this is what good historian does in order to evaluate whether a source is reliable. The historian looks for other independent sources that corroborate the history of the primary source. If there is a great deal of matching facts, then the source is considered highly reliable. For instance, Luke speaks in His Gospel many times of Jesus' interaction with historical persons who can be cound in other records and inscriptions. Therefore, Luke's record is considered to be accurate. It is also a fact that the greatest historians of ancient times were the Jews. That is why Josephus and Trypho are considered to be so valuable in corroborating the Gospel accounts and Acts.
The Egyptians, like the Romans, kept tons of records. There is no record of the Jews ever being in Egypt.
Archaeologists have discovered the Stele of Mernptah whic contains the following inscription:
Israel is wasted, bare of seed,
Khor is become a widow for Egypt.
All who roamed have been subdued.
By the King of Upper and Lower Egypt
According an article at Wikipedia:
"Rameses II, is commonly considered to be a pharaoh with whom Moses squabbled - either as the 'Pharaoh of the Exodus' himself, or the preceding 'Pharaoh of the Oppression' who is said to have commissioned the Hebrews to "(build) for Pharaoh treasure cities, Pithom and Raamses." These cities are known to have been built under both Seti I and Rameses II, possibly making his successor Merneptah 'Pharaoh of the Exodus.' This is considered plausible by those who view the famed stele of Merneptah's 5th year (ca. 1208 BC), claiming that 'Israel is wasted, bare of seed,' as propaganda covering up his own loss of an army in the sea."
Here is another interesting article giving some archaeological evidence that the Hebrews escaped from Egypt.