We know that Paul was held under some brutal conditions—his feet in stocks in one case. Yet he was still able to write many letters from prison. Was this during some of his "nicer accommodations", or did the ethos of the time allow visitors and outside contact (even as they tortured prisoners)?
In contrast, in the US, when someone has done something pretty offensive (murderers to terrorists), there are controversies about and often restrictions placed on their writings (esp. the ability to publish books, but sometimes more general limitations on outside contact, etc.)