What is the origin of fustian?

The noun fustian has several meanings: “a stout fabric of cotton and flax; fabric of stout cotton or of cotton and low-quality wool; inflated or turgid rhetoric.” Middle English has the forms fustian, fustain, fustein (and still others), all from Old French fustai(g)ne. The Middle English word means only “a kind of cloth made from cotton, flax, or wool (not necessarily coarse or of poor quality); a coverlet of such cloth to be spread over a bed or mattress.” As with many widespread cultural items, such as cloth and clothing, luxury items (wine, perfume), weapons, and foods (rice, turkey), the etymology of fustian is complicated. The Middle English and Old French words come from Medieval Latin fūstāneum, fūstiānum, fūstānum, which may be a derivative of Latin fūstis “stick, cudgel,” used as a loan translation of Greek xýlina lína “cotton,” literally, “wood linen” (the cotton plant is woody, unlike flax, the source of linen). Another suggested source for fūstāneum is Fostat, a suburb of Cairo, where fustian was manufactured. Fustian entered English about 1200. The adjective is derived from the noun.