Dionysius of Tell-Mahre was the Patriarch of Antioch and head of the Syriac Orthodox Church from 818 until his death in 845 CE (wikipedia). He wrote Annals in Syriac in the first half of the 9th century CE. Annals is a two volume history which covers events from 582 - 843 CE. The first volume is devoted to church history - the second to secular history. Each volume is subdivided into 8 books each. Only a few fragments of his original work survives however he is a source in other author's chronicles such as Michael the Syrian and Chronicon Ad Annum 1234. Michael the Syrian explicitly cites Dionysius of Tell-Mahre as a source and Brock(1976) suggests that "the lost chronicle of Dionysius of Teilmahre appears to be one of the main sources" for Chronicon Ad Annum 1234 during "this period". In his preface, Dionysius of Tell-Mahre states that he used Theophilus of Edessa as a source ( Hoyland, 1997:416-419). Further details on Dionysius of Tell-Mahre can be found in a book by Abramowski (1940).