Sir William Ramsay, who at first was a skeptical archeologist, after 30 years of study, had this to say about Luke and the book of Acts. "Luke is a historian of the first rank; not merely are his statements of fact trustworthy...this author should be placed along with the very greatest of historians. Lukes history is unsurpassed in respect of its trustworthiness". Colin Hemer catalogued numerous archaeological and historical confirmations of Luke's accuracy in his book "The Book of Acts in the Setting of Hellenistic History" Roman Historian A.N. Sherwin-White said, "For Acts the confirmation of historicity is overwhelming...Any attempt to reject its basic historicity must now appear absurd. Roman historians have long taken it for granted."
I do not believe we can question Luke's historical accuracy in the book of Acts. It has been questioned before, and found to be extroadinary. 500 people eyewitnessing Jesus after the ressurection, and His being here for 40 days before the Ascenscion, is just one part of the big puzzle. If one truly searches, as I have, I do not see how one could conclude anything but that the new testament is true, and that Jesus is who he claimed to be.
SOMETHING happenned to the disciples on the day of pentecost! They went from cowering in their room to proclaiming the gospel. As far as dying for a cause, if they had NOT seen Jesus after he rose again, they would NOT die for it. But as they HAD seen him, they could not deny it, and did not. Here is the rub, many people have died for something they BELIEVED to be true, nobody will die for something they DO NOT believe to be true, unless they are insane. These men ALL died for what they believed except John who was exiled to Patmos. I believe they did indeed see Jesus after he rose again, and at pentecost were empowered by the Holy Spirit to proclaim it.