Demas had at one time been one of Paul’s “fellow workers” in the gospel ministry along with Mark, Luke, and others (Philemon 1:24). During Paul’s first imprisonment in Rome, Demas was also in Rome (Colossians 4:14).
There is also biblical evidence that Demas was with Paul during Paul’s second imprisonment in Rome, at least for a while. Then something happened. Demas forsook Paul, abandoned the ministry, and left town. Paul wrote about the sad situation: “Demas, because he loved this world, has deserted me and has gone to Thessalonica” (2 Timothy 4:10).