Luke said that “Many have undertaken to draw up an account of the things that have been fulfilled among us.” Not among ‘them’. This happened, and it happened in his lifetime. All of ancient history was most often written by people who lived long after the events, and they would cobble together the different accounts and writings and try to put together an accurate and reliable description of what happened. But very rarely do we have anyone in all of ancient history who actually lived during the time of the person and the events that they wrote about…like we have with the separate and individual authors of the separate and individual books that comprise the New Testament.
