Paul and Timothy, servants of Christ Jesus, To all the saints in Christ Jesus who are at Philippi, with the overseers and deacons:This is a typical greeting by the Apostle. He refers to himself as a servant (or bond slave) of Christ Jesus. From this greeting, we can see that he is currently with Timothy. It is believed that Paul is in Prison in Rome during the writing of this letter, and he will make reference to such imprisonment later in this first chapter.
(Philippians 1:1, ESV)
The saints at Philippi that we know of (from Acts) are Lydia. a seller of purple, a poor slave girl, who had been a fortune teller, and a jailer, employed at the Philippian jail.