Tralles is a small town on the highway into Ephesus. Confusingly, it has had several names -- in Roman times it was renamed Caesarea, and under Turkish government became Aydin, which is its current name.

It is not clear that Ignatius actually visited the church of Tralles, but he did meet their Bishop, Polybius, in Smyrna. Polybius seems to have told him about unorthodox ideas that were current in Tralles.

The first is mentioned in Chapter 5, and seems to imply some kind of Gnosticism, including esoteric information about angels and heavenly principalities. Ignatius rather charmingly says that he is too young in the faith to have any knowledge of such ideas, but counsels against pursuing them.

He is more forceful in countering a form of Docetism, which believed that Jesus was pure spirit, and any observation of his body, and particularly of his suffering and death, was illusory. Ignatius drily observes that if Jesus only "seemed to exist" then perhaps the Docetists only "seemed to exist" and perhaps he and his suffering were only illusions.........

As an aside, why was Ignatius still travelling to Rome for execution, when persecution in Syria appeared to have ceased? However, those in the group with first-hand experience of the ways of bureaucracies had little difficulty with the thought that once the mechanism of sending him to Rome was under way, it would be difficult -- and perhaps nobody's responsibility -- to reverse.