a Greek monk who flourished in the latter half of the 14th century at AEneus, in Thracia, wrote about 1373, when he is said to have been at the age of sixty, Computus Graecorums de solemnitatepascha, tis celebrandi, published in Greek and Latin by J. Christmann (Heidelberg, 1611, 4to), and inserted by Dionysius Petavius in his De Doctrina temporum (3, 359). He is also supposed to be the author of a work still in MS. form on astronomy. Of Isaac's personal history but little is clearly known. — Jocher, Gelehrt. Lex. 2. 1984; Mosheim. Eccl. Hist. bk. 3, cent. 14, pt. 2, ch. 2. (J. H.W.)