Composition of the Four Gospels

The canonical Four Gospels, Matthew, Mark, Luke, and John, are understood to have been composed between 70 and 110 CE.

None of the Four Gospels actually identifies its author by name, though the traditions about authorship are based on very early Christian writings that identify them. About 50 Gospels were written in the first and second century CE, each believed to be accurate by various groups within the early Christian movement.

Persecution of the early Christians by the Romans, before Christianity was adopted by the Emperor Constantine in 313, undoubtedly contributed to the scarcity of early Christian documents. 

"The relationship of early Christianity to the Jewish faith, and the foundation of the cult deeply rooted in a people accustomed to religious intolerance actually helped it take hold initially. The Jews were accustomed to resisting political authority in order to practice their religion, and the transition to Christianity among these people helped foster the sense of Imperial resistance. To the Romans, Christians were a strange and subversive group, meeting in catacombs, sewers and dark alleys, done only for their own safety, but perpetuating the idea that the religion was odd, shameful and secretive. Rumors of sexual depravity, child sacrifice and other disturbing behavior, left a stigma on the early Christians. Perhaps worst of all was the idea of cannibalism. The concept of breaking bread originating with the last supper, partaking of the blood and body of Christ, which later came to be known as Communion, was taken literally. To the Romans, where religious custom dictated following ancient practices in a literal sense, the idea of performing such a ritual as a representation was misunderstood, and the early cult had to deal with many such misperceptions" (http://www.unrv.com/culture/christian-persecution.php, accessed 12-04-2008).