I have been doing some research on Nero looking for data that might help in the interpretation of Philippians, which I believe should be placed in Rome in the early 60's when Nero was on fire. One interesting offshoot has been comparing the sources we have for Nero with those we have for the Gospels. The three main sources we have for Nero are Tacitus, Suetonius and Dio Cassius. The first, Tacitus or Publius/Gaius Cornelius Tacitus lived from AD 56-117. So he was born 2 years after Nero came to power and was 10 when Nero died. So he did not experience Nero first hand, although he might have seen him. He was a senator and historian, at one point Governor of Asia (AD 112/113). He was a part of the scene when Domitian was at his peak of despotic mania. He drew on earlier sources like Pliny the Elder which are lost. The work of most interest to study of Nero, Annals (Annales), was written sometime in the period AD 110-120, likely at the latter end of the decade. This is some 50-60 years after the event. We have only two incomplete manuscripts, one from AD 850, nearly 8 centuries after the event (Ch. 1-6), the other from the eleventh century (Ch. 11-16). We do not have the material on Nero's childhood and youth, nor the final two years of his life.
Suetonius or Gaius Suetonius Tranquillis lived from around AD 70 to 130. He worked mostly as Hadrian's palace librarian. He wrote Lives of the Twelve Caesars (De Vita Caesarum or Casares) which has a section on Nero. It is thematic rather than chronological. It was likely written at the end of the same decade as Tacitus' Annals, around 119 – so also around 50 years after Nero.
The third main source is Cassius Dio who wrote a Roman History from its origins to AD 229 indicating that it was completed in the early 3rd century, some 160 years after Nero. Dio was a senator, consul in AD 204, 229 proculsul of Africa, and at various points governor of Dalmatia and Upper Pannonia. The section on Nero is found in 11th-12th Century Byzantium material, some 1000 years after Nero. Further, the manuscripts have not been copied with care and have a lot of comments from the scribes making interpretation difficult.
We have a bit of data in Flavius Josephus who joined the Romans in the rebellion of AD 66-73 and has scattered references to Nero which tell us little of real detail.
The three sources have a lot of similar material but deviate at points. One can put together a good life of Nero from it, but at points of detail one has to try and reach a conclusion with some variance from the sources. We don't have historians questioning the existence of Nero, or many of the elements of his life – but we do have debates about whether the history casts him in too bad a light, and over detail.
If we come to the Gospels we have four works about Jesus, and scattered details of his life through the 25 Epistles and Revelation. There are also many writings about Jesus in the centuries that followed, based in the main on the records in what is now called the NT. We have to remember when we read the NT that it was originally separate documents not a book as we have it, and brought together as as unit. This is important because each part needs its own analysis, rather than the whole thing. When we look at the sources for Jesus as compared for Nero, the data comes out at least comparably if not better.
Mark is likely dated in the 60's. We have one testimony that he drew on first hand evidence from Peter (Papias). He may also be an eye-witness if he is the 'nude-guy' in the garden in Mark 15 which cannot be verified. If he is not mind you, one wonders what on earth that little piece is doing in Mark's Gospel? So, it is some 27-37 yrs after Christ. Unlike Tacitus, Suetonius and Cassius Dio, we cannot verify that he had written sources, although it cannot be ruled out that the disciples took down material and/or that Mark or a proto-Mark existed in Aramaic.
The date of the other three Gospels are debated. Luke is dated at 62-63 by some, including myself on the basis that it ends with Paul in Roman prison and says nothing about a set of major events in the 60's (James death in Jerusalem, Paul leaving Rome and further ministry (if it occurred), Paul and Peter's death, Paul's letters, the Fall of Jerusalem). Luke uses Mark, which would mean Mark should be dated before this, maybe at 60-61. This is not an issue because using Luke and the letters, Mark and Luke are in Rome together in the early 60's. Other scholars would date Luke in the 70-80's. If so, it is some 40-50 yrs after Christ, still less than the gap between Nero and Tacitus or Suetonius. Luke also refers to written sources in his prologue. One of these written sources may be the mysterious and unverifiable Q (Quelle – source), the common material in Luke and Matthew. He must have drawn on others because he has a lot of unique material. So, we have at least three sources. Like a good ancient historian, he also refers to speaking to eye-witness testimony from those who worked with Christ (Lk 1:1-4). As such, Luke should be considered at least as reliable as Tacitus and Suetonius, even more so perhaps, if the earlier date is to be trusted.
Matthew is usually dated at a similar point to the later Luke date, but gives no evidence of written sources. We can deduce two, Mark and Q, and probably at least one other as he has substantial independent material. As such, Matthew too can be considered a reliable record compared to the material for Nero.
Then we have John. John seems to be dated later, 80-100, although some argue for a pre-70 date because of the temple. Still, even if we date it in the 90's in Domitian's reign as would seem the latest it should be dated to me, it is still less than 70 years after the event. This would place it alongside Suetonius and well ahead of Cassius Dio as a source. If John is the apostle, and this is heavily disputed, then we have an eye-witness and friend of Jesus writing, enhancing its authenticity.
Then there is the material in Paul written earliest (c. AD 48-66) and the other letters and Revelation, all in the first century, about the same time distance from Jesus as Nero.
Further, we have fragments of mss and many mss from much closer than the 9th-12th century compared to the one or two incomplete mss we have on the three sources for Nero. We can trace carefully through Textual Criticism what is likely the original text. While we can't finally get there, we are close to the original of each NT document.
The only real advantage one can argue for the records of Nero over Jesus is that the Romans were very much a literary culture took down substantial material, but much of the earlier material is lost to us. Still, the Christians demonstrated quickly that they too were a literary culture.
Putting it together, surely we have as much reason to trust the Gospels as we do for the historical records of Nero. Apologists can use this material as they contend against those who say that the Gospels and NT are unreliable. What do you think?