What is a “Gospel”?
The word “Gospel” comes from the Greek word euangelion meaning “good news. Mark 1:1 says he is writing, “the beginning of the good news about Jesus Christ.” Gospel is a new kind of genre. It's a biography with the purpose to tell and challenge people with the life of Jesus.
Believe it or not, the word “gospel” actually appears in the Old Testament. In Isa 52:7, it mentions a person who “brings good news” (an evangelist). If you were a Roman or a Greek person you thought of “good news” (gospel) as news about a victory in battle or the birth of a king's heir.
Early Christians considered “gospel” to be the message about Jesus's life and death (1 Thess 1:5). Peter, John, Phillip, and Paul all preached a message called “gospel” (Acts 8:25, 40; 14:7; 15:7; 16:10; Rom 1:9). Later the word came to mean the books themselves in which the gospel message was written.
How Did We Get the Gospels?
After some time the preaching about Jesus's life was written down by the apostles and other followers of Jesus. Each of the four authors had different approaches and emphases giving us four gospels instead of one monochromatic message. As the end of the apostolic age approached, Christians were confronted with the challenges of persecution and the impending deaths of eyewitnesses who walked and talked with Jesus. The message was then written down to preserve it for many generations to come and to put the authoritative message into a portable form to send to other churches and peoples who would never be able to hear the apostles themselves preach.
Two of the Gospel writers were eyewitnesses to Jesus himself: Matthew and John. The other two, Mark and Luke, were secondary witnesses but knew and traveled among the apostles Paul, Peter, and others (1 Pet 5:13; Acts 12:12; Col 4:14; 2 Tim 4:11). But they did not write without the influence of the Holy Spirit who “brought to remembrance” all the teachings of Jesus at the appropriate time (John 14:26).
It is very likely that Mark was the first Gospel written because of it's short length and the fact that most of Mark is also found in Matthew and Luke. Luke himself even mentions “others who wrote before me” (Luke 1:1–2) which may have included Mark.
Over the course of time, Christians began to collect the Gospels into four-book volumes often containing the Gospels and Acts and a second volume containing Paul and other writings. These books were eventually assembled into complete New Testament books not unlike what we have today. They were copied in Greek and then in Latin until about the time of Martin Luther when he and several other Reformers sought out the original Greek manuscripts that had been so long neglected. Today most modern Bibles rely on the oldest Greek manuscripts available. While we don't have the “original autographs” that Paul or Mark themselves wrote, we do have very good copies that date to as early as AD 100s. These oldest manuscripts are then compiled and translated into modern-language editions we have with us.
Who Was Mark?
Mark never mentions himself by name in the Gospel (but neither do the others). John Mark's family was from Judea near Jerusalem. His mother's house was a gathering place in the early days of the Jerusalem church (Acts 12:12). He was the cousin of Barnabas (Col 4:10) and his inclusion in Paul's work caused a rift between Barnabas and the Apostle. Later Mark was restored to Paul and shared a close relationship with him in his last days (Col 4:10; Phlm 24; 2 Tim 4:11). He also seems to have been a close associate with Peter while in Rome / “Babylon” (1 Pet 3:15).