Heidegger's Bible Handbook: Philippians: Place of Writing

4. It was written at Rome from bonds, the former, not the latter.

This Epistle appears to have been the first among the Epistles written by Saint Paul in his former bonds, whereby he was kept in custody at Rome. While he was captive at Rome (for, that it was written in bonds, is evident from Philippians 1:7, 13, 14; and that it was written at Rome, not Jerusalem, is gathered from Philippians 1:13; 4:22; and finally, that it was written in the former, not latter, bonds, his hope of continuing his ministry argues, Philippians 1:19-26), the Philippians, being more than a little concerned about him, sent Epaphroditus, to visit him in his bonds, and to supply to him the necessary supports of life, Philippians 2:25; 4:10, 18. The same Epaphroditus Paul sent back to the Philippians, Philippians 2:28, and committed to him this Epistle for delivery. The Subscription witnesses to the same, which thus reads: πρὸς Φιλιππησίους ἐγράφη ἀπὸ Ῥώμης δι᾽ Ἐπαφροδίτου, it was written to the Philippians from Rome through Epaphroditus. For, that it was sent through Timothy also, as the Arabic version has it, is not probable, both because in Philippians 2:19 Paul signifies that he was going to send Timothy to them shorty: and because the Epistle was writing in the names of Paul and of Timothy.