The term “Apostolic Fathers” refers to the Christian leaders who ministered during the late first and early second centuries. They are called “Apostolic” because their lives overlapped with the time period of the Apostles, and in fact, some of them are traditionally believed to have personally known and studied under one or more of the twelve Apostles. The Apostolic Fathers whose names we know with certainty are Clement of Rome, Ignatius of Antioch, and Polycarp of Smyrna. Their letters (along with a few anonymous writings) make up the earliest Christian documents we possess outside the New Testament itself.