Gospel according to Luke 1:1-4
Forasmuch as many have taken in hand to set forth in order a declaration of those things which are most surely believed among us, even as they delivered them unto us, which from the beginning were eyewitnesses, and ministers of the word; it seemed good to me also, having had perfect understanding of all things from the very first to write unto thee in order, most excellent Theophilus, that thou mightest know the certainty of those things, wherein thou hast been instructed.
Eusebius of Caesarea, Ecclesiastical History II.xv.1, xvi.1
But a great light of religion shone on the minds of the hearers of Peter, so that they were not satisfied with a single hearing or with the unwritten teaching of the divine proclamation, but with every kind of exhortation besought Mark, whose Gospel is extant, seeing that he was Peter's follower (ἀκόλουθον), to leave them a written statement of the teaching given verbally . . . They say that this Mark was the first to be sent to preach in Egypt the Gospel which he had also put into writing, and was the first to establish churches in Alexandria itself.Eusebius, Ecclesiastical History, 1:141 and 143.
The Revelation of Jesus Christ, which God gave unto him, the shew unto his servants things which must shortly come to pass; and he sent and signified it by his angel unto his servant John: Who bare record of the word of God, and of the testimony of Jesus Christ, and of all things that he saw. Blessed is he that readeth, and they that hear the words of this prophecy, and keep those things which are written therein: for the time is at hand.
I John who also am your brother, and companion in tribulation, and in the kingdom and patience of Jesus Christ, was in the isle that is called Patmos, for the word of God, and for the testimony of Jesus Christ. I was in the Spirit on the Lord’s day, and heard behind me a great voice, as of a trumpet, saying I am the Alpha and the Omega, the first and the last: and, What thou seest, write in a book, and send it unto the seven churches which are in Asia; unto Ephesus, and unto Smyrna, and unto Pergamos, and unto Thyatira, and unto Sardis, and unto Philadelphia, and unto Laodicea.
The Evangelist most frequently shown on Byzantine seals is St. John. The Dumbarton Oaks and Fogg Museum seal collections contain a variety of different depictions of the saint. A seal showing John reading can be seen on the introductory page for this section. On the first example, top left, John is shown at his writing desk, crafting his Gospel; while on the second seal, top right, John is seen dictating his Apocalypse to his assistant Prochoros.
St. Mark is rarely represented on Byzantine seals. Byzantine tradition named him as either Peter's assistant or son, and compiler of a Gospel dictated to him by the Apostle (as depicted on the section title page, bottom left). On the example here, right, he is shown as a young man, holding his Gospel. The depiction of St. Luke, above left, in military attire, holding a spear and shield, does not conform to Byzantine artistic norms. Traditionally Luke is depicted at his writing desk, or simply as a young man.