The History of the Methodology of the Gospels

Some of my own teachers at Harvard Divinity School taught this way which was to say well there is a core wisdom tradition within the New Testament. Once it went into these Greco-Roman cities then it got somehow altered where you started to see you know well we must appeal to pagans or it got kind of urbanized in a way. I couldn't quite understand why you would make that jump and so I started to become really interested in why do we create these elaborate backstories for these texts?