He wrote also a Koran commentary, now apparently lost, and a hortatory epistle to Harlan al-Rashid.
They produced a brilliant succession of eminent scholars and scientists who transmitted to the Moslems the results of Babylonian civilization and Greek learning, and their influence at the court of Baghdad secured more or less toleration for Sabianism, although in the reign of Harlan al-Rashid the Harranians had already found it necessary to establish a fund by means of which the conscientious scruples of Moslem officials might be overcome.
Harlan consented and Yahya went to Bagdad, where he met with a splendid reception.
Dreading fresh insurrections of the Alids, Harlan secured the person of another descendant of Ali, Musa b.
The building of the fortress of Iladath having been completed, Harlan committed to Faraj the Turk the task of rebuilding and fortifying the city of Tarsus.