The biography of Luke developed early and stuck fast. By the early fourth century, Eusebius—the bishop of Caesarea and the father of church history—had identified most of the traditions that scholars puzzle over today. In his Ecclesiastical History (c. 312–324), Eusebius wrote:

Luke, being by birth one of the people of Antioch, by profession a physician, having been with Paul a good deal, and having associated intimately with the rest of the apostles, has left us examples of the art of curing souls that he obtained from them in two divinely inspired books—the Gospel, which he testifies that he wrote out even as they delivered to him who from the beginning were eyewitnesses and ministers of the word, all of whom [or “all of which facts”] he says he had followed even from the beginning, and the Acts of the Apostles, which he composed, receiving his information with his own eyes, no longer by hearsay.

Ecclesiastical History 3.4

The church father Jerome (347–420) could add few details to Eusebius’s account:

Luke the physician, an Antiochian, as his writings show, was not ignorant of the Greek language. The follower of the apostle Paul and comrade of all his travels, he wrote the Gospel, of which the same Paul says, “We have sent together with him the brother whose praise is in the gospel through all the churches”; and to the Colossians, “Luke the beloved physician greets you,” and to Timothy, “Only Luke is with me.” He also published another excellent volume, which is designated by the title, “apostolic Acts,” the narrative of which extends up to the two-year period in Rome, that is, to the fourth year of Nero. From this also we learn that the book was written in the same city. Some suspect that whenever Paul says in his letters “according to my gospel” he means the volume of Luke, and that Luke had learned the gospel not only from the apostle Paul, who had not been with the Lord in the flesh, but also from the rest of the apostles. And this he also declared himself in the beginning of his volume saying, “Even as they delivered to us who from the beginning were eyewitnesses and ministers of the word.” The Gospel, therefore, he wrote as he had heard; but the Acts of the Apostles he composed as he had seen. His tomb is at Constantinople, to which city his bones, together with the remains of the apostle Andrew, were transferred in the twentieth year of Constantius.

De Viris illustribus

In his Preface to the Commentary on Matthew, Jerome further noted:

The third [evangelist], Luke the physician, by birth a Syrian of Antioch, “whose praise is in the gospel,” and himself a disciple of the apostle Paul, composed his book in the districts of Achaia and Boeotia, investigating some things from an earlier time, and, as he himself confesses in his preface, describing what he had heard rather than what he had seen.