The story of Jesus recounted in the Christian Gospels could not have happened. At the time of Jesus, the Romans were in full control of the region, through their prefects and the client king Herod they had elevated to the throne after defeating the Hasmoneans. The Romans were meticulous record keepers, and they recorded none of the key stories in Gospel, including Massacre of the Innocents, the supposed crowds of Jesus' followers in Jerusalem, the judgement of Pontius Pilate, and the Crucifixion. If these things had happened, the Romans would have recorded them, and they didn't. So, these stories are all fiction, and they were likely invented by The Apostle Paul, and his followers, who founded a religion based on Jesus' resurrection.
Paul's inventions came after the historically true assassination of James, the so called "brother of Jesus," who had a popular sect in Jerusalem that came to odds with the High Priest Ananus ben Ananus who ordered James's assassination. Paul was a hanger in the court of King Herod who intended to marry someone there, and he claimed he witnessed the assassination of James, which is quite possible. He certainly heard of it not long after.
But Paul's invention of Jesus didn't come from nothing. He was aware of much that had been happening before the assassination of James. He was surely aware of key ideas from James's sect, which had been becoming too popular for the likes of Ananus. He may have talked with James, which is what the Gospels say, and even been a part of James's sect.
Those ideas likely involved the teachings of a figure earlier than Jesus, The Teacher of Righteousness, the key figure in the Dead Sea Scrolls. The Teacher was a much earlier figure, from either the first or second centuries BCE. Millennialism was a primary feature of these teachings (also reflected in some of the Gospels) that the coming of God was at hand in about 40 years, and when that didn't happen many turned away his sect but others changed the story. The Teacher was persecuted by "The Wicked Priest" in Jerusalem who is unnamed and historians can only speculate which one he is. The Teacher was ultimately put to death by unnamed authorities. This may or may not have been before the Romans defeated and isplaced the Hasmoneans.
But along with the Millennialism, The Teacher taught some if not many of the virtues which would be familiar to Christians. The followers of The Teacher, the Essenes, were a communal sect foreshadowing the later communal sects of Christianity. This brings to mind The Sermon on the Mount, and in fact the Beatitudes have a striking resemblance to some of the teachings in the Dead Sea scrolls (eg, blessed are the poor in spirit), though the caves where they were found is some distance from the site traditionally believed to be where Jesus is said to have given the Sermon.
One historian tried to advance the theory that The Teacher was Jesus, and this has never been very well accepted because the dates are so far apart. But this is not what I am saying. I am saying that The Teacher was likely part of the inspiration for the story of Jesus, which was an fictional invention of Paul and his followers. The Teacher was probably also an inspiration for the sect of James, though James's teaching might have been quite different from Paul's and likely lacked key parts of Christianity like the Resurrection and the notion that Jesus was God. Jewish Christianity which is said to have been the continuation of James's sect also lacks the idea that Jesus was God, merely an important human teacher, and Islam incorporates that view.
The Herodian court held that the assassination of James was illegal and Ananus was deposed. Not long afterward, the Revolts were begun with Ananus as a key leader, and lasted for years until the Romans sacked the Temple. The Romans seem to have sided with the followers of James in that even when Jews were forbidden to enter Jerusalem after the later Bar Kochba revolt, Jewish Christians were not. Jewish Christians understood themselves to be fundamentally Jewish and followers of the Torah, though they were excluded from both Judaism and Christianity centuries later, and many converted to Islam after that.