ar-is-tar'-kus (Aristarchos, "best ruler"):
He was one of those faithful companions of the apostle Paul who shared with him his labors and sufferings. He is suddenly mentioned along with Gaius as having been seized by the excited Ephesians during the riot stirred up by the silversmiths (Acts 19:29). They are designated "men of Macedonia, Paul's companions in travel." We learn later that he was a native of Thessalonica (Acts 20:4; 27:2). They were probably seized to extract from them information about their leader Paul, but when they could tell nothing, and since they were Greeks, nothing further was done to them.
When Aristarchus attached himself to Paul we do not know, but he seems ever after the Ephesian uproar to have remained in Paul's company. He was one of those who accompanied Paul from Greece via Macedonia (Acts 20:4). Having preceded Paul to Troas, where they waited for him, they traveled with him to Palestine. He is next mentioned as accompanying Paul to Rome (Acts 27:2). There he attended Paul and shared his imprisonment. He is mentioned in two of the letters of the Roman captivity, in the Epistle to the church at Colossians 4:10, and in the Epistle to Phm (Philemon 1:24), in both of which he sends greetings. In the former Paul calls him "my fellow-prisoner." According to tradition he was martyred during the persecution of Nero.
S. F. Hunter