Epistles of Ignatius
Ignatius of Antioch penned these letters to churches (Ephesians, Magnesians, Trallians, Romans, Philadelphians, and Smyrnaeans) and Polycarp on his way to martyrdom. Ignatius was an apologist for the Episcopal style of church government (as opposed to sole rule by a council of presbyters) which developed in the late first or early second century. Eager to die in imitation of his Savior, it was Ignatius who wrote this to the Roman church: "I am God's wheat, and I am ground by the teeth of wild beasts that I may be found pure bread [of Christ]." (Summary by Sam Stinson)