Polycarp is the third of the Apostolic Fathers, with Ignatius and Clement. His death can be dated by one formula to 156 CE, and by another to 170. In the well-regarded Martyrium of Polycarp, he is quoted as having said "Eightysix years have I served my master -- should I blaspheme him now?" This indicates that, like John the Apostle, he lived to a great age, and to some extent supports the claim that he was a disciple of John, though which John is perhaps unclear.

His Letter to Philippi is a cover letter, enclosing a package of letters by Ignatius for study by the Philippians. In contrast to the sometimes harsh tone of the letters of Clement and Ignatius, he "comes across" as a friendly, tolerant personality. There are even contemporary jokes told about him, particularly his encounters with Cerinthus and Marcion, and even in the arena facing imminent death.