Aristar'chus (Α᾿ρίσταρχος, best ruler, a frequent Greek name), a faithful adherent of the Apostle Paul in his labors. A.D. 51-57. He was a native of Thessalonica, and became the companion of Paul in his third missionary tour, accompanying him to Ephesus, where he was seized and nearly killed in the tumult raised by the silversmiths (Ac 19:29). He left that city with the apostle, and accompanied him in his subsequent journeys (Ac 20:4), even when taken as a prisoner to Rome (Ac 27:2); indeed, Aristarchus was himself sent thither as a prisoner, or became such while there (Phm 1:24), for Paul calls him his "fellow-prisoner" (Col 4:10). The traditions of the Greek Church represent Aristarchus as bishop of Apamea in Phrygia, and allege that he continued to accompany Paul after their liberation, and was at length beheaded along with him at Rome in the time of Nero. The Roman martyrologies make him bishop of Thessalonica.