Note 5 at Phil. 2:26: Paul's statements about Epaphroditus give us clues as to how long Paul had been imprisoned in Rome at the time of the writing of this letter.

The Philippians had to hear that Paul had finally reached Rome. In those days, news of Paul's whereabouts was not sent to them by means of tele-communications. An individual had to physically travel from Rome to Philippi and deliver the message. This would have taken a minimum of weeks and possibly a month or more. Then the Philippians had to send Epaphroditus with aid for Paul from Philippi to Rome, which would again have entailed lengthy travel.

Once Epaphroditus reached Rome, a period of at least two months would have elapsed since Paul had reached Rome. It could easily have been longer. Then Epaphroditus became ill and news had to travel back to Philippi, and the response of the Philippians had to travel back to Rome, for Epaphroditus to know that the Philippians had heard of his sickness.

The shortest time in which these events could have taken place would have been a minimum of three to four months and it could easily have taken place over a year's time. Thus, Paul was imprisoned in Rome for two whole years (Acts 28:30). This letter was written at least months after Paul arrived in Rome and possibly towards the latter part of his Roman imprisonment (see DATE AND PLACE OF WRITING in INTRODUCTION TO THE BOOK OF PHILIPPIANS, p. 1149).