I ask you because I can find no evidence for who wrote any of the gospels. I was hoping you could supply some.
The early church unanimously held that the gospel of Matthew was the first written gospel and was penned by the apostle of the same name (Matt. 10:2-4). Lately, the priority of Matthew as the first written gospel has come under suspicion with Mark being considered by many to be the first written gospel. The debate is far from over.
The historian Papias mentions that the gospel of Matthew was originally in Aramaic or Hebrew and attributes the gospel to Matthew the apostle.5
•"Irenaeus (ca. a.d. 180) continued Papias’s views about Matthew and Mark and added his belief that Luke, the follower of Paul, put down in a book the gospel preached by that apostle, and that John, the Beloved Disciple, published his Gospel while residing in Asia. By the time of Irenaeus, Acts was also linked with Luke, the companion of Paul."6
This would mean that if Matthew did write in Aramaic originally, that he may have used Mark as a map, adding and clarifying certain events as he remembered them. But, this is not known for sure.
The earliest quotation of Matthew is found in Ignatius who died around 115 A.D. Therefore, Matthew was in circulation well before Ignatius came on the scene. The various dates most widely held as possible writing dates of the Gospel are between A.D. 40 - 140. But Ignatius died around 115 A.D. and he quoted Matthew. Therefore Matthew had to be written before he died. Nevertheless, it is generally believed that Matthew was written before A.D. 70 and as early as A.D. 50.