In academic circles, three of the four canonical Gospels (Matthew, Mark, and Luke) are regarded as so similar in wording and content that they are often treated as one unit, the synoptic gospels. According to the majority of scholars, the solution to the synoptic problem of similar content and dependence is the two-source hypothesis - that the three synoptic gospels are not totally independent but derive from two source texts, one being the Markan priority, the other being a hypothetical lost collection of logia (sayings) known as the Q document, and the few remaining elements unique to Matthew or to Luke are known as M or L, respectively. No ancient gnostic text explicitly refers to an original document of sayings. The oldest extant fragments of gospels are of John, and by tradition Mark