In Siege of Baghdad (1258) [0], "...Mongol soldiers looted and then destroyed mosques, palaces, libraries, and hospitals. Priceless books from Baghdad's thirty-six public libraries were torn apart, the looters using their leather covers as sandals. Grand buildings that had been the work of generations were burned to the ground. The House of Wisdom (the Grand Library of Baghdad), containing countless precious historical documents and books on subjects ranging from medicine to astronomy, was destroyed."<p>[0]: <a href="https://en.wikipedia.org/wiki/Siege_of_Baghdad_(1258)" rel="nofollow">https://en.wikipedia.org/wiki/Siege_of_Baghdad_(1258)</a>