Martyr and former slave. He is mentioned in St. Paul’s Letter to Philemon as the slave of Philemon in Colossae, Phrygia, who ran away. Paul met Onesimus while the former was in a Roman prison, and Paul baptized the slave and came to consider him his own son. Paul sent Onesimus back to Philemon with the epistle, asking Philemon to accept him “no longer as a slave, but more than a slave, a brother, beloved especially to me, but even more so to you, as a man in the Lord. So if you regard me as a partner, welcome him as you would me. And if he has done you any injustice or owes you anything, charge it to me”. In Paul’s Letter to the Colossians, Onesimus is again mentioned as accompanying Tychicus, the bearer of the letter. The pre-1970 Roman Martyrology incorrectly identifies Onesimus with the bishop of Ephesus who followed St. Timothy as bishop of Ephesus and who was stoned to death in Rome.

With thanks to Catholic Online