The 27 books of the New Testament were written between 50 AD and 150 AD and written in Greek. The language of Jesus and his disciples was Aramaic and most were likely lower class people and at least two of them were known to be illiterate according to Acts. The four Gospels were written anonymously between 35 and 95 years after the death of Jesus and all are written in the third person. The titles of them as the Gospels according to Matthew, Mark, Luke and John were all made at least 100 years after they were written by well educated Greek speakers.

(The Great Courses – The New Testament)