Over two decades ago, I read, in a biography of the Apostle Saint Paul, the hypothesis that his letters were posthumously collected by Onesimus, who is mentioned in (and is the main subject of) the Epistle to Philemon. Unfortunately, I cannot now cite that biography; but the idea of that collection is definitely not mine.
A subscript to the Ephesian epistle, often appearing in older printings of the KJV, indicate that the letter was delivered to its recipients by Tychichus.
Several scholars believe that the presently titled Epistle to the Ephesians is actually the Laodicean letter mentioned in Colossians 4:16.
My own contribution to the discussion is the response of the Laodicean Christians to the letter, a response suggested by Revelation 3:14-19, in which their spiritual arrogance is described and condemned by Christ Himself.
The Apostle's relationship with the Laodicean church is not, presently, known.
