From Irenaeus, in Adversus Haeres, Book III, Chapter 3, Verse 4 (circa AD 180):
“But Polycarp was not only instructed by the apostles, and conversed with many who had seen Christ, but was also, by apostles in Asia, appointed bishop of the church in Smyrna…..always taught the things which he had learned from the apostles, and which the church has handed down, and which alone are true. To these things all the Asiatic Churches testify, as do also those men who have succeeded Polycarp down to the present time…..There is also a very powerful Epistle of Polycarp written to the Philippians, from which those who chose to do so, and are anxious about their salvation, can learn the character of his faith, and the preaching of the truth.”