The Importance Of Rome's Testimony About Luke's Authorship

My last post mentioned some corroboration of Lukan authorship of the third gospel from sources predating Irenaeus (Marcion and his earliest followers, Justin Martyr, a Roman source Irenaeus cited). People often claim that Irenaeus provides the earliest attribution of the third gospel to Luke, but these sources move the earliest attribution and some partial corroboration of it prior to when Irenaeus wrote.

And notice how all three of these pre-Irenaean sources are connected to Rome. Marcion was in Rome, Justin Martyr spent some time there, and Irenaeus' source seems to be Roman.

Paul traveled to Rome multiple times, spent a long time there, and died in that city. The author of Luke and Acts claimed to be a close companion of Paul and frequently discusses him and refers to traveling with him, including going with Paul to Rome around the time when the third gospel was published (Acts 28:14). Given the nature of the events leading up to and following Acts 28:14 and the recording of a large amount of detail in the author's recounting of the events, there's a good chance that the author used his time in Rome to do a lot of his work composing Acts. That would have provided some opportunities for the author (and Paul and whoever else) to have had discussions with the Roman Christians about the writing of the gospel and its sequel. Even if his work on Luke/Acts while in Rome was of a lesser nature, such as just taking some notes, that sort of situation would also have some significance here. If Colossians and Philemon were written from Rome, Colossians 4:14 and Philemon 24 place Luke there, and 2 Timothy 4:11 has Luke in Rome again later on. The references to Mark with Luke in Roman contexts (Colossians 4:10, Philemon 24, 2 Timothy 4:11) add to the likelihood that issues involving Luke's gospel would have been discussed.

This puts critics of the traditional gospel authorship attributions in a bad position. How likely is it that there would be so many early literary references to Mark and Luke in Rome (more than what I've cited above), including references to their being in the city for so long and in such significant contexts, if they hadn't been there? And if they were there, how likely are the Roman Christians to have been as ignorant as skeptical hypotheses require them to have been regarding Mark and Luke's relationships with the gospels attributed to them? The Roman church was in a good position to have reliable information on the authorship of the third gospel (and its genre, historicity, etc.). So, not only do we have testimony on the authorship of that gospel predating the testimony of Irenaeus, but we even have it from such significant sources.