Early dating of the gospels
The criterion of cultural and historical congruency says that a source is less credible if the account contradicts known historical facts, or if it conflicts with cultural practices common in the period in question.It is, therefore, more credible if it agrees with those known facts.Erasmo Leiva-Merikakis notes that "we must conclude, then, that the genre of the Gospel is not that of pure 'history'; but neither is it that of myth, fairy tale, or legend.In fact, 'gospel' constitutes a genre all its own, a surprising novelty in the literature of the ancient world." New Testament scholar, James D. Dunn believes that "the earliest tradents within the Christian churches [were] preservers more than innovators...seeking to transmit, retell, explain, interpret, elaborate, but not create de novo...Scholars can also look into the internal evidence of the documents, to see if, for example, the document is misquoting texts from the Hebrew Tanakh, is making claims about geography that were incorrect, if the author appears to be hiding information, or if the author has made up a certain prophecy.
Most scholars hold to the two-source hypothesis which claims that the Gospel of Mark was written first.
When judging the historical reliability of the gospels, scholars ask if the accounts in the gospels are, when judged using normal standards that historians use on other ancient writings, reliable or not.