Medieval Islamic Swords and Swordmaking: Kindi's Treatise "On Swords and Their Kinds" - Paperbackby Robert G. Hoyland (Author), Brian Gilmour (Author) One of the problems pervading the study of medieval Islamic technology is the lack of surviving technical treatises. Tradition tended to be handed down by example and by word of mouth, and apprenticeships could last for decades. Fortunately, however, occasional treatises do exist. The treatise "On swords and their kinds" was written by the 9th century Muslim philosopher Ya'qub ibn Ishaq al Kindi.