distinguished Christian theologian, historian, philosopher, exegete, and grammarian, who became bishop of Edessa (c. 684). His strict discipline giving offense, he retired and devoted himself to study and teaching.

Jacob composed Syriac homilies in prose and verse, canons, liturgies, commentaries on the Old and New Testaments, and a chronicle, designed to continue that of Eusebius, of which only fragments remain. He revised the Peshitta (oldest and possibly the most simple version of the Bible) Old Testament on the basis of Greek and Syriac versions. He also translated from the Greek, notably the Homiliae cathedrales of Severus of Antioch. Jacob produced the earliest extant Syriac grammar and introduced Greek letters to represent the Syriac vowels.