(c. a . d . 130),1 a Greek au th o r , who wrote a musical catechism in form of a dialogue : Isagoge musicae artis ; first published by Mersenne in 1623, with a F rench trans lation in his Harmonie universelle, 1627; also one by Ruelle, 1896. The treatise, n o t in dialogue form, which was published by Fr. Bellermann in 1841 an d tran s la ted into French by A. J . H. Vincent as th a t of Bacchius, is n o t by him b u t by his contemporary, Dionysios. e . v . d. s. 1 R iemann says 4th century a . d .