Paul writes Ephesians, Colossians, and Philemon
Ephesians 6:21–22; Colossians 4:7–9; Philemon 1:10–16
From prison Paul sent Tychicus to Asia with three letters: Colossians, warning against a false teaching that belittled Christ; Ephesians, on the church as Christ's body; and Philemon, asking a master to welcome back his runaway slave Onesimus as a brother.
for by grace you have been saved through faith, and that not of yourselves; it is the gift of God, not of works, that no one would boast.
Ephesians 2:8–9 (World English Bible)
Onesimus had met Paul in prison and become a believer; he traveled back with Tychicus (Colossians 4:9). Colossians presents Christ as the image of the invisible God, in whom all things hold together (Colossians 1:15–17); Ephesians celebrates Jews and Gentiles made one new people in him.
Dating notes
Most date these letters to Paul's Roman imprisonment, about AD 60–62; some suggest Caesarea or an imprisonment at Ephesus. Ussher: AD 64. The date is an estimate; Scripture doesn't say when the book was written.