The Double Standard from Skeptics When we are looking at secular history, historians come across balanced, fair, reasonable but when it comes to the gospels, there is a tremendous double standard. The Gospels, for example, are presumed to be guilty of being frauds, authors unknowable until they are proven innocent, and the bar is raised when it comes to the level of evidence needed. The normal way of investigating historical events, peoples, and places ostensibly are thrown out the window.
PAPIAS (c. 60-135 A.D.) and the Gospels of Matthew and Mark
There is much in-depth information in this article: The Synoptic Gospels in the Ancient Church: The Testimony to the Priority of the Gospel of Matthew. We have a brief introduction to papyrus from Tyndale Bible Dictionary. We have a lengthy apologetic article on Papias and the arguments from higher critics by F. David Farnell. This is followed by Papias' writings from two leading scholars on the Apostolic Fathers, Michael W. Holmes, and J. B. Lightfoot.
The Synoptic Gospels In Early Christianity: Why Is the Preferred Choice the Testimony to the Priority of the Gospel of Matthew?
The Enlightenment and its spawning of historical-critical methodologies—particularly that aspect of the system called "Source Criticism"—marked the beginning of the end of the priority of the Gospel of Matthew.