ARISTACE (RASTAKES). - The younger son of s. Gregorio Illuminatore, educated in Cesarea di Cappadocia, he chose the eremitical life at a young age, until Tiridate, king of Armenia, summoned him from his hermitage to Valaršapat and had him ordained priest and auxiliary bishop to his father, the first katholikos of Christian Armenia.
A. was also sent by s. Gregorio to the Council of Nicaea (cf. Gelzer-Hilgenfeld-Cuntz, Patrum Nicaenorum nomina, Lipsia 1898, pp. LVI, LXII), as representative of the Armenian Church, and brought its canons to Armenia; when s. Gregorio withdrew into solitude in his final years, he left the see of katholikos to A., who was his worthy successor (325-33). He was killed by Arcesilao, prince of Quarta Armenia, whom he had reproved for his licentious life.