T‘oros, a Chalcedonian Armenian, ruled the city of Edessa (mod. Şanlıurfa, Turkey), nominally on behalf of the Byzantine Empire, in the period after the Turkish invasions of Upper Mesopotamia in the late twelfth century, holding the titles of doux and kouropalates.
In 1095, however, T‘oros was forced to accept the presence of a Turkish garrison in the citadel of Edessa. After their expulsion, he strengthened the fortifications and maintained a strong armed force, although he became unpopular because of his heavy taxation of the local population. In 1098 he requested the assistance of Baldwin of Boulogne, who had arrived with the armies of the First Crusade (1096-1099) and was then campaigning in the Upper Euphrates Valley. Though contemporary accounts are contradictory, T‘oros probably offered Baldwin a share in the government of Edessa and may even have adopted him as his son and heir.
After an unsuccessful campaign to Samosata, Baldwin returned to Edessa, where dissident Armenians in the city overthrew T‘oros. He was murdered while trying to escape, having been warned of the plot by Baldwin, whose role in the affair is unclear.