Marcion of Sinope
Marcion of Sinope was the first Christian leader in recorded history (though later considered heretical) to propose and delineate a uniquely Christian canon (c. AD 140). This included 10 epistles from St. Paul, as well as a version of the Gospel of Luke, which today is known as the Gospel of Marcion. By doing this, he established a particular way of looking at religious texts that persists in Christian thought today.