Paul wrote five of his thirteen letters from within a Roman jail cell. While the book of Acts ends with Paul under house arrest, apparently at some point Paul is moved to a more secure form of prison where he is fettered in chains. What might that have looks like? From the entry on “Prisons, and Prisoners” by B.M. Rapske, in The Dictionary of New Testament Background:
Prisoners suffered various privations in custody. War and civil disturbance, the enforcement of condemnatory edicts and delay in processing cases owing to volume, incompetence or sheer malice could pack prisons far beyond reasonable capacity. Poor ventilation created conditions of dangerously stale air, suffocating heat and dehydration. Prisons were sleepless places. Where pallets were not available one slept on the floor, perhaps using one’s outer cloak as a cover against the cold (Josephus Ant. 18.6.7 §204; cf. Acts 12:8; 2 Tim 4:13). Chains and stocks (xyla) also hindered sleep (Lucian of Samosata Tox. 29; Acts 16:24-25).
Most prisons were devoid of much natural light. In their inner cells and underground chambers, light was nonexistent. Small wonder that tenebrae (“darkness”) can be rendered “dungeon” in some passages (e.g., Cicero Cat. 4.10). Nightfall robbed prisoners of natural light, and the requirements of security forbade them artificial light (Tertullian Ad Mart. 2; Mart. Let. Lyons et Vienne 27-28; Mart. Perp. et Felic. 3.5; cf. Acts 16:29).
The chaining of prisoners caused varied consequent sufferings. Iron chafed and corroded the skin over time (Lucan Civ.W. 72-73; Seneca Contr. 1.6.2; cf. Phil. 1:17). Tightly fixed, chains were a means of torture (Cod. Theod. 9.3.1). Prisoners could also be weighed down with such heavy chains as to exhaust or cripple them (ARS 8–XII Tables 3.3; Ovid Con. Liv. 273-74; Suetonius Nero 36.2; Seneca Contr. 1.6.2; Philostratus Vit.Ap. 7.36).
Without recourse to personal resources or the help of friends on the outside for food or drink (Josephus Ant. 18.6.7 §204; Life 3 §§13-14; Lucian of Samosata Peregr. 12; Tertullian De Jejun. 12; b. Moed Qať. 3:1-2; b. Moed III: (Erub. 21b; cf. Acts 16:34; 24:23; 27:3), the prisoner’s prospects could be grim. The officially provided daily prison ration (solo fiscalis) was poor and intended not for health but bare survival. Its denial could be a punishment, a form of torture or even a means of execution (Dio Cassius Hist. 58.3.5-6; Tertullian De Jejun. 12; Christian Martyr Literature passim; Heliodorus Aeth. 8.6.2; Cyprian Ep. 21.2; 33.2; cf. Acts 16:25, 33-34).
Prisons were places of squalor and appalling filth (Cicero Verr. 2.5.21; Tertullian Ad Mart. 2; Cyprian Ep. 47.3). The permissions of a lighter custody might allow for new clothing and visits to the public baths (Josephus Ant. 18.6.7 §203; 18.6.10 §228; Tertullian De Jejun. 12; Justinian Dig. 48.20.2, 6), but barber’s knives were a risk and so haircuts were denied (Martial Epigr. 3.74; Josephus Ant. 16.11.16 §§387-88; 18.6.10 §237; Lucian of Samosata Tox. 30; m. Moed Qať. 3:1). Clothing quickly turned to rags in severe custody so prisoners came to look more dead than alive (Lucian of Samosata Tox. 30). Even before entering custody, the action of mobs and the normal process of punitive or coercive flogging left clothing and bodies torn (Seneca Contr. 9.2.21; Acts 16:22; 21:30-32; 22:24-25).
It is not a surprise that these awful conditions caused such profound distress of body and soul that prisoners, if they did not become sick and die (Seneca Contr. 9.1; Plutarch Vit. Cim. 4.3; Philostratus Vit.Ap. 4.35; 7.26; 8.22; cf. Mt 25:36, 43), wished themselves dead or actively sought suicide (Philostratus Vit.Ap. 7.26; Lucian of Samosata Tox. 30; Tacitus Ann. 6.5.8; Suetonius Vitellius 7.2.3; Tiberius 61.5; Dio Cassius Hist. 58.3.5-6; Justinian Dig. 48.3.8; 220.127.116.11-5).
Mediterranean culture was significantly driven by honor and shame concerns, and in such a context the experience of custody and bonds carried devastating dishonor and shame connotations. Prisons and shame are closely identified in the literature (Plutarch Vit. Sol. 15.2-3; Pausanius Test. 6.13.1; Cicero Verr. 2.5.148; Arrian Epict. 1.4.23-24; 2.1.35; 2.6.25; Suetonius Vitellius 7.17; Seneca Ep.Lucil. 85.41). Damaging connotations and insult attached to prisoners irrespective of their deserts because prison was by definition for social deviants (Dio Cassius Hist. 58.11.1; Seneca Contr. 9.4.20-21; Suetonius Vitellius 7.17.1; Philostratus Vit.Ap. 7.34). The process of being publicly conducted in chains was intended to degrade prisoners (Dio Cassius Hist. 58.11.1.F; Suetonius Vitellius 7.17.1; cf. Josephus J.W. 2.12.7 §246), and it inspired a general and sometimes lifelong revulsion of the prisoner (Philostratus Vit.Ap. 7.34-37; Dio Chrysostom De Ser. 1.22 [§14]). Terms for prison and its accoutrements were applied derisively, including “jail guard” (custos carceris), “fetter farmer” (catenarum colonus), “ex-convict and jail bird” (ex compedibus atque ergastulo) and “jail bird” (desmotes). Even friends and close associates experienced great pressure to abandon the prisoner (Seneca Ep.Lucil. 9.9; Philostratus Vit.Ap. 4.37; Lucian of Samosata Tox. 18, 28-29; Antiphon De Caed. Her. 18; Mart. Perp. et Felic. 5.2). It might be added that the same connotations attended those who had been publicly stripped and flogged (Justinian Dig. 48.19.28; 50.2.12).
The severe circumstances of these conditions make the command of Hebrews shine much more clearly: Remember those who are in prison, as though in prison with them, and those who are mistreated, since you also are in the body. – Hebrews 13:3. But it also provides insight into exactly what kind of world Paul was inhabiting as he was writing letters like Philippians, Colossians, and Ephesians, where he says things like:
“Now I rejoice in my sufferings for your sake,” – Col 1:24
“Not that I am speaking of being in need, for I have learned in whatever situation I am to be content.” – Phil 4:11