Q source
It was written in Greek, for a gentile audience, and probably in Rome, although Galilee, Antioch (third-largest city in the Roman Empire, located in northern Syria), and southern Syria have also been suggested. Early Christian tradition, first attested by Papias of Hierapolis (c. 60– c.130 AD), attributes it to the John Mark mentioned in Acts, but scholars generally reject this as an attempt to link the gospel to an authoritative figure. The author used a variety of pre-existing sources, such as conflict stories, apocalyptic discourse, and collections of sayings (although not the Gospel of Thomas and probably not the Q source).