Philippi was founded by Philip pf Macedon to administer the silver mines in the area.  It became a major city, sited on the main roads to Rome (the Appian Way) and to Byzantium (Via Egnatia).  It was the site of the climactic battle between the army of Brutus and Cassius and the army of Octavian.  After the Battle of Actium, the survivors of the losing side were resettled in Philippi, which became a full Roman city, administered with Roman law, and with its inhabitants granted Roman citizenship. 

When Paul and Silas arrived there, on Paul’s Second Missionary Journey, they ran afoul of vested commercial interests, were beaten and thrown into prison.  An earthquake freed them from prison, but they refused to leave until the local magistrates personally escorted them out. The magistrates, learning that Paul and Silas were Roman citizens, were only too anxious to do so

Paul writes to Philippi from prison.  There is some discussion as to the city of the prison, but refers to a sympathetic audience in the praesidium, a term usually reserved for the Guards’ headquarters in Rome.  However, Paul writes as if within easy traveling distance of Philippi, so some prefer to think in terms of his imprisonment in Ephesus, about which little is known.  A third candidate is Caesarea Maritima, where Paul was under arrest by Roman military units.

Did Paul contemplate suicide?  One passage in Philippians can be read that way, but the group was unsympathetic to the idea.

Chapter Two contains what looks like all or part of an early Christian hymn.  It uses high Christology, describing a pre-creation Christ, who “emptied himself” to become man – what is known as Kenotic theology.

Epaphroditus had been sent from Philippi to look after Paul.

Chapter 3 starts with “Finally ----- “ with two more chapters to go.

Chapter 4 contains a remarkable piece of "bible study" that on the face of it is a misreading of a verse from Psalm 68, wrenched out of context, and apparently misquoted (though possibly Paul was quoting the Septuagint rather than the Hebrew). Throughout the Epistles there is the question as to whether Paul felt it reasonable to quote short passages out of context. Conceivably he carried with him a set of "useful quotations" rather than a complete set of Hebrew sacred literature.

Chapter 5 has a section on Christian living, similar to the corresponding section in Colossians, unappealing today for its subservient view of women and its acceptance of slavery as an institution.

Verse 12 of chapter 6 seems to take gnostic terminology for granted, with its talk of "archons" and heavenly powers. As in several epistles it talks of "heavens" and the possibility of traveling between them.

Was Paul a prisoner when the letter was written? The phrase at the start of Chapter 4 is "Paul, a prisoner in Jesus Christ", so it might be that Paul is speaking metaphorically, as he does when referring to himself as a "slave of Christ". However, it is rather more difficult to apply that argument to the phase "an ambassador in a chain" in Chapter 5.

Was Aslan inspired by Roger Lancelyn Green's tiger?

Does the Ring in The Lord of the Rings represent a nuclear weapon?

C.S. Lewis applies the techniques of biblical criticism to some 20th century literature, with surprising results.

http://members.tripod.com/orthodox-web/papers/fern_seed.html