Of few saints of the sub-apostolic generation is the documentary chain so short. Ignatius himself wrote seven letters during the last weeks of his life, and these survive in his own hand; that is the principal source. Within ten or twenty years of his martyrdom, his fellow-disciple Polycarp of Smyrna wrote to the Philippians, mentioning Ignatius by name, asking the Philippians to send on whatever further information they had about him, and forwarding to them the collection of letters that Polycarp himself had been able to gather. Two generations later, Saint Irenaeus of Lyons, who had himself been a disciple of Polycarp, quotes Ignatius in the closing book of his Against Heresies. A generation after that, Origen of Alexandria quotes him in a Homily on Luke. And by the time of Eusebius of Caesarea (writing about AD 320), the seven letters and the basic facts of Ignatius's life are firmly part of the church's memory; Eusebius gives him a chapter of his Ecclesiastical History.

Eusebius's chapter is the earliest connected biographical notice. Polycarp's mention is fifteen or twenty years from the event. Irenaeus's quotation is about eighty. By the standards of ancient hagiography this is a remarkably small space.

Ignatius was bishop of the church in Antioch of Syria, the city in which, as Saint Luke records (Acts 11:26), the disciples were first called Christians. Eusebius gives the succession of the see: the Apostle Peter himself was reckoned as the first, then Evodius, then Ignatius. The dates of Ignatius's episcopate are not given by any ancient source with precision; the chronicle that Eusebius compiled in his Chronicon assigns him a long tenure, perhaps something like forty years, and the universally received tradition has been that he came to the see in the early 70s of the first century and held it until his removal to Rome under Trajan around AD 107. He calls himself 'bishop of Syria' in the letters, plural Syria being then the Roman province of which Antioch was the chief city.

His own name for himself is 'Theophorus,' God-bearer. He uses the name in the opening of each of the seven letters. He gives no explanation of it; later piety supplied the story (still current in many menologia) that he was the child whom the Lord set in the midst of his disciples and said, 'Whosoever shall humble himself as this little child, the same is greatest in the kingdom of heaven' (Matt. 18:1-4). This identification is not in any ancient source and is reckoned by careful hagiographers as a piece of medieval devotion rather than as biography; the name 'Theophorus' more probably means simply that he was carried by God to the death he had asked for, or that as a bishop he carried God in himself.

Under the emperor Trajan, in a persecution local to Syria, Ignatius was condemned to die by the wild beasts at Rome. The condemnation is reported by Eusebius and is the assumed background of every one of the seven letters. He was bound and given over to ten Roman soldiers for the journey overland; the soldiers were not gentle. He describes them in his own Epistle to the Romans (chapter 5) as 'ten leopards, who only become worse when they are kindly treated.' The party went from Antioch up the Syrian coast, across Asia Minor by the great Roman road, and at last to Smyrna on the Aegean, where they paused for some days before going on through Troas to Macedonia and Italy.

The pause at Smyrna gave Ignatius the opportunity to write. The bishops of the surrounding cities of Asia Minor — Onesimus of Ephesus, Damas of Magnesia, Polybius of Tralles — sent delegations to greet him; he wrote back, sending each delegation home with a letter for its church. He also wrote ahead to the Roman Christians, begging them not to use their influence at the imperial court to have his sentence commuted. This is the first batch: the Epistles to the Ephesians, the Magnesians, the Trallians, and the Romans. From Smyrna the party went on to Troas, and there, the persecution at Antioch having ended and his own martyrdom now no longer in his way, he wrote three further letters: to the Philadelphians, to the Smyrneans, and to Polycarp personally. That is the seven; the older tradition counted no more authentic.

Polycarp, after Ignatius's death, gathered these letters together and forwarded copies of them to the Philippians (Polycarp, Phil. xiii). It is by his hand that the corpus has come down to us.

Ignatius came at last to Rome and was killed in the amphitheatre, by the wild beasts. The bare fact of this is given by Eusebius (Ecclesiastical History III.36, ad fin.) without further detail; it is the same end that Ignatius had himself written in advance to the Romans that he wanted, and that he had begged them not to obstruct. Eusebius dates the event to the tenth or eleventh year of Trajan (AD 107 or 108); Jerome's De Viris Illustribus 16 says the eleventh year of Trajan, AD 109. The differences are small. The Orthodox calendar keeps his memory on the twentieth of December.

After the death the Christians of Rome gathered what the beasts had left of his bones and carried them back to Antioch, where they were laid to rest. The transferral is mentioned in passing by Saint John Chrysostom in his own Homily on Ignatius (PG 50, col. 587-596), preached at Antioch about AD 388 over the very relics. Later, in 637, when Antioch fell to the Arabs, the relics were taken to Rome and laid in the church of Saint Clement; later still they were translated again to the basilica of Saint Peter, where they rest.