The Regional Letters: Paul’s Network in Asia Minor. When we think of Paul’s letters, we often divide them into categories like “Prison Epistles” or “Pastoral Epistles.” These categories are helpful, but they do not fully capture the web of connections that link certain letters together by geography, personnel, and theme. A closer look at Ephesians, Colossians, Philemon, and 1 & 2 Timothy reveals that they function as regional letters.