The Iliad is fiction.
Neither could the supernatural events described in the Gospels.
Which eye witnesses were still alive when each of the gospels were written. The time period in question is ~70CE to ~90CE. Give evidence for your claims.
Where is your evidence that any of these people were still alive when the gospels were written.
5,000 people witnessed the death and resurrection of Gerald my pet hamster. You need to start worshipping him now.
I am going back to this post because we diverted to the witnesses to Saul's experience on the road to Damascus and then somehow onto celestial mechanics. We had a very good talk at church before Christmas, on Luke 1, the story of Zechariah, the father of John the Baptist.
As I said, the Iliad was probably written centuries after the events it was based on. Luke, however introduces us to his first eyewitness in 1:5, "In the time of Herod king of Judah there was a priest named Zechariah, who belonged to the priestly division of Abijah; his wide Elizabeth was also a descendant of Aaron." Note here the historical context (Herod, king of Judah) and the family tree of both John's parents. Luke is telling Theophilus exactly who the eyewitness is. That this is a real eyewitness is evident because he avoids boasting about meeting an angel, confessing that he didn't believe his message, which if someone had made a false claim, would be unlikely.
Now the person giving the sermon called attention to verse 3 where Luke says that he had investigated everything from the beginning. Thus, to answer to your question, eyewitnesses handed down the things that had been fulfilled among them, and Luke has investigated everything so that Theophilus could be sure of what he had been taught.