Mansour Zalzal

Manṣūr Zalzal al-Ḍārib or simply Zalzal, was an Iranian musician during the early Abbasid period. The renowned musician Ishaq al-Mawsili was his student; he declared Zalzal to be the most outstanding lutenist of his time.
He contributed musical scales that were later named after him : the Mansouri scale, Arabic, المقياس المنصوري.
He introduced positions within scales on the fretboard of an oud, called wusta-zalzal.
Mansour is credited by the Encyclopedia of Islam with making improvements on the design of the barbat lute, which was then called the ūd shabbūt.