The Letters of Paul
There are thirteen Epistles written by the apostle Paul:
Romans, 1 and 2 Corinthians, Galatians, Ephesians, Philippians, Colossians, 1 and 2 Thessalonians, 1 and 2 Timothy, Titus, and Philemon.
Within this group is a subgroup labeled the Prison Epistles (Ephesians, Philippians, Colossians, and Philemon) so-called because they were written during Paul’s two-year house arrest in Rome (Acts 28:30–31).
The Pastoral Epistles (1 and 2 Timothy and Titus) were written to church leaders and include many teachings regarding practices within the early church.
(Note: Description used with permission from www.gotquestions.org)