You are wrong about Josephus' writings. He wrote "The Jewish War" in 75 A.D. As a historian, he was familiar with events just before his lifetime. He mentions both Jesus and John the Baptist. We also know that Pontius Pilate was a real person--a tablet bearing his name, and dated to the time period of Jesus, was found in Israel. Josephus also mentions Pilate, who is also mentioned by Tacitus and Philo of Alexandria.
After the Crucifixion and Resurrection of Christ, strange things happened in the temple. When the lots for the goats were chosen by the high priest on the Day of Atonement, the priest always picked the black lot first--considered a bad omen. Black lots were picked from the Crucifixion until the destruction of the temple in 70 A.D. The odds of that happening year after year from 33 A.D. to 70 A.D. are about one in 5 billion. Also, when the red sash was cut in two and one part retained by the high priest, and the other part placed on the scapegoat, the red cloth NEVER turned white as it did in years past. The heavy bronze doors to the temple would also open by themselves every night--it took 20 men to move them, but they opened by themselves. The light on the menorah closest to the Holiest of Holies would always go out--it would not stay lit. Finally, just before the temple's destruction, Josephus records that a strange white light permeated the entire temple at night for a few hours, and then went out. This was perceived as the spirit of God leaving the temple. Now--these facts are recorded in the Jerusalem Talmud, which, Serenity, is a JEWISH source. The Sanhedrin blamed all of these happenings on Jesus. What is NOT in dispute is that they HAPPENED.
Some of Paul's letters are dated from around 55 - 60 A.D. The Gospels themselves were written from around 60 - 70 A.D. The synoptic Gospels were written by people who KNEW the original Apostles; the Gospel of John was supposedly written by the Apostle John himself--John the son of Zebedee.
Islam, if you recall, was spread by the armies of Islam after the death of Muhammad. Christians and Jews living in conquered lands were required to pay a heavy tax, the jizyah, to their new overlords or face execution. The Muslim Crusades predate the Christian Crusades by centuries. Both were bloody affairs. Right after the death of Muhammad, his son-in-law and cousin, Ali, was killed in internecine warfare.
Finally, the Apostles were NOT fanatics. They were scared s***ss after the Crucifixion. There is quite a difference between people like that and fanatics. Fanatics have limited capacity for reason. The Apostles preached with both reason and the words of Jesus on their side.
Christianity is not a myth. It is real. And the truth is there for those who will but seek it.