When was the "Evangelist" title first applied to the Gospel authors?

When was the “Evangelist” title first applied to the Gospel authors?

An exact date is impossible to ascertain, but their are a few glimmers of light on this subject.

First of all, let us look at what it is to be an evangelist in the broadest sense.

Etymology

The word evangelist comes from the Koine Greek word εὐαγγέλιον (transliterated as euangelion) via Latinised evangelium as used in the canonical titles of the Four Gospels, authored by (or attributed to) Matthew, Mark, Luke, and John (also known as the Four Evangelists). The Greek word εὐαγγέλιον originally meant a reward given to the messenger for good news (εὔ = "good", ἀγγέλλω = "I bring a message"; the word "angel" comes from the same root) and later "good news" itself.

The verb form of euangelion, (translated as "evangelism"), occurs rarely in older Greek literature outside the New Testament, making its meaning more difficult to ascertain. Parallel texts of the Gospels of Luke and Mark reveal a synonymous relationship between the verb euangelizo (εὑαγγελίζω) and a Greek verb kerusso (κηρύσσω), which means "to proclaim".

The title of *Evangelist as being first uniquely applied to the Sacred Writers of the four Gospels was in fact something that came about gradually.

At one point this term was used to be given to readers during the sacred liturgy. After all, the priests and deacons were the sacred ministers who read the Gospel at mass!

Gradually it became confined to the writers of the Four Gospels. It is exclusively in this sense that common modern usage employs it.

St. Paul, in his list of the gifts bestowed by Christ for the edification of the Church, Ephesians 4:11 (in 1 Corinthians 12:28, they are omitted), mentions the evangelists in the third place, only after the Apostles and the Prophets. In the writings of the Apostolic Fathers, no reference is made to evangelists; travelling missionaries are sometimes called "apostles", sometimes also, as in the Didache, they are styled "teachers".

In the later ecclesiastical literature the word evangelist, perhaps sporadically still used for some time in its old sense (Eusebius, Church History V.10), received in most parts of the Church, another meaning. Applied occasionally to the reader in the Liturgy (Apost. Const., III), even to the deacon (Lit. of St. John Chrysost., P.G., LXIII, 910), it became gradually confined to the writers of the Four Gospels (Eusebius, Church History III.39, etc.. It is exclusively in this sense that common modern parlance employs it. - Evangelist

Eusebius of Cæsarea, (260-341) Bishop of Caesarea Maritima and Father of the Church, was a historian of Christianity, exegete, and Christian polemicist. He adds the following insights about the title of evangelist in his Church History (Book III):

Chapter 37. The Evangelists that were still Eminent at that Time.

4. But since it is impossible for us to enumerate the names of all that became shepherds or evangelists in the churches throughout the world in the age immediately succeeding the apostles, we have recorded, as was fitting, the names of those only who have transmitted the apostolic doctrine to us in writings still extant.

Thus I believe that the term Evangelist only applied to the writers of the four Gospels came about sometime in the late third or early fourth century. This can only be applied to more traditional conservative Christian believers such as Catholics and Orthodox. Some modern denominations employ this term for preachers of one kind or another.

Lots of good answers here and I'll offer something I just read in the new Word on Fire Bible, it's not a perfect answer but I think it's enough to an answer to stand alone.

Bishop Barron writes:

Euangelion (glad tidings) was a familiar word in the culture of the New Testament authors. When the emperor or one of his generals won a battle, he would send evangelists ahead to announce the glad tidings.

The first Christians were being consciously edgy when they adapted this word to their purposes

Word on Fire Bible - Volume 1 - PP 70.

So, according to Bishop Barron like other words brought over from Roman Military (i.e. sacrament / sacramentum which means a sacred oath) in the early church, anyone who spread the gospel was called an Evangelist. If you consider the four gospel writers to be real people, their title of "The Evangelist" is just one more title for a few of them.

And because most scholarly types cast a shade of doubt on whether the actual Apostles and follower of the Apostles were the authors of their gospels, they don't necessarily doubt there that there is a reason for these books to be named as they are:

Even critical scholars who doubt the traditional attributions of authorship agree that these five books were written by followers of Matthew, Mark, Luke, and John, which still puts them in a good place to tell the stories accurately.

https://www.christianitytoday.com/edstetzer/2012/february/closer-look-historical-reliability-of-new-testament.html

So if you'll indulge me this semi-frame challenging answer, the term evangelist refers to the fact that they really must have done the job of spreading the Good News, not necessarily their authorship alone.

The earliest source I can find comes from Eusebius of Cæsarea's Church History written in the 4th century AD. The Catholic Encyclopedia states the following

In the later ecclesiastical literature the word evangelist, perhaps sporadically still used for some time in its old sense (Eusebius, Church History V.10), received in most parts of the Church, another meaning. Applied occasionally to the reader in the Liturgy (Apost. Const., III), even to the deacon (Lit. of St. John Chrysost., P.G., LXIII, 910), it became gradually confined to the writers of the Four Gospels (Eusebius, Church History III.39, etc.. It is exclusively in this sense that common modern parlance employs it.

The section where this excerpt was taken from mentions the four evangelists around 13 times. Click here for the whole link. CTRL + F then search evangelist. It begins in Chapter 7.

These things took place in this manner in the second year of the reign of Vespasian, in accordance with the prophecies of our Lord and Saviour Jesus Christ, who by divine power saw them beforehand as if they were already present, and wept and mourned according to the statement of the holy evangelists, who give the very words which he uttered, when, as if addressing Jerusalem herself, he said:

Here is another excerpt from the same Catholic Encyclopedia Article of Evangelist

As early as the second century, Christian writers sought in Ezechiel's vision (i, 5 sqq.) and in Apoc. (iv, 6-10) symbolical representations of the Four Evangelists. The system which finally prevailed in the Latin Church, consisted in symbolizing St. Matthew by a man, St. Mark by a lion, St. Luke by an ox, and St. John by an eagle (see SYMBOLISM). It is fully explained by St. Jerome (In Ezech., i, 7) and had been adopted by St. Ambrose (Expos. Ev. S. Luc., Proœm.), St. Gregory the Great (In Ezech., Hom. I, iv, 1), and others. St. Irenæus, on the one hand, and Augustine, followed by the Venerable Bede, on the other, had devised different combinations. Christian artists followed in the footsteps of the ecclesiastical writers, and made use, in different manners, of the four traditional figures to represent the Evangelists. Among the most remarkable works of this description it will suffice here to mention only the old mosaics of the churches of S. Pudentiana, S. Sabina, S. Maria Maggiore, and S. Paolo fuori le Mura, at Rome.

I hope that this helps you.