One of the most important innovations in human history, printing, was the ability to reproduce copies of the written word for mass consumption and distribution. Printing has taken many forms over the centuries, dating back to ancient Sumer, when documents were pressed into clay using cylinders. Methods of printing patterns onto cloth evolved into means of printing, and in ancient China, woodblock printing and eventually movable type made book printing possible throughout China, Japan, and Korea. The 16th century was a period of massive change within the printing world as new inventions and methods revolutionized how people read.