What gospel is the origin of the synoptic gospels?

All the New Testament gospels were originally anonymous and were only attributed to the apostles whose names they now bear later in the second century. The first gospel was the one now known as Mark's Gospel.

Scholars can demonstrate that the Gospels of Matthew and Luke were largely based on Mark's Gospel, even having exactly the same Words in the Greek language. Matthew and Luke also shared a sayings source, now known as the hypothetical 'Q' document. Scholars also say that John's Gospel is loosely based on Luke's Gospel, with some material taken direct from Mark. So the synoptic gospel that was the starting point for the other gospels is Mark's Gospel.

It is uncertain where the author of Mark's Gospel obtained his source material. Raymond E. Brown (An Introduction to the New Testament) simply says that Mark seems to depend on traditions (and perhaps already shaped sources) received in Greek. It is possible that Mark's Gospel could have been influenced by the Gospel of Thomas, a sayings gospel, but that is at best a minority opinion among scholars who continue to debate whether Thomaswas even written during the first century.