- The Letter to the Ephesians asked them to show obedience to their Bishop, Onesimus (who was probably the slave whom St. Paul sent back to his master, Philemon, with the letter we consider part of Scripture). Ignatius places emphasis on participation in the Eucharist, and he gives us the great quote, "The Eucharist is the medicine of immortality".
- The Letter to the Magnesians stressed obedience to their Bishop, Damas. He exhorted them to be sincere in their Christian life and to beware of Judaizers (a group of radical Jewish Christians who saw Christianity as simply a sect of Judaism).
- The Letter to the Trallians showed his concern about Docetism (a heresy that held that Jesus only seemed to be human; that he did have two natures, but the divine nature won our over the human nature). He stressed the Incarnation of Christ: fully God and Man, and asked the people to stay loyal to their bishop and priests.
- The Letter to the Romans has a different tone: there the church has order and they're not struggling with heresies. He shows reverence and respect for the Bishop of Rome. Knowing that he's going to be killed in Rome, he asks them not to try to interfere or attempt to free him. This is the most famous of Ignatius' letters, with the quote, "Suffer me to be eaten by the beasts, through whom I can attain to God. I am God's wheat, and I am ground by the teeth of wild beasts that I may be found pure bread of Christ." He also refers to the guards assigned to him as "leopards", who become angrier with him as he gets kinder to them.
- The Letter to the Philadelphians urges unity and loyalty. There's lots of problems in Philadelphia, amongst them the problems of both Judaizers and Docetists. He stresses that there be one Eucharist only, since there had probably been "rival" Eucharists established. "Abstain from evil growths,", Ignatius writes, "which Jesus Christ does not tend, because they are not of the planting of the Father."
- The Letter to the Smyrnans is full of many references to particular people, since Ignatius spent some time there in confinement, and thanks them for kindness shown to him. It is in this letter that we first hear the term "Catholic Church": "Wherever the bishop appears let the congregation be present; just as wherever Jesus Christ is, there is the Catholic Church. (καθολική εκκλησία)."
- The Letter to Polycarp of Smyrna is almost a companion to the previous letter. Ignatius' and Polycarp's friendship goes back to the days of being with St. John. Ignatius is giving Polycarp advice on how to exercise the office of Bishop. He uses lots of similes, among them he compares the episcopacy with athletes: "'Bear the sicknesses' of all as a perfect athlete.", and, "Be sober as God's athlete."
Eventually, Ignatius gets to Rome and is killed in the lion pit. His followers collected whatever pieces of his remains that they could, and brought them back to Antioch in Syria. Eventually some of his remains made their way back to Rome, and you can still visit them, should you visit the Eternal City. St. Ignatius' head (or at least a skull believed to be his head) can be found in the sacristy of the Gesù, while an arm of Ignatius' is under the main altar in the church of San Clemente, along with the remains of Pope St. Clement.