While paper used for wrapping and padding was used in China since the 2nd century BC,[1] paper used as a writing medium only became widespread by the 3rd century.[9] By the 6th century in China, sheets of paper were beginning to be used for toilet paper as well.[10] During the Tang Dynasty (618–907 AD) paper was folded and sewn into square bags to preserve the flavor of tea.[1] The Song Dynasty (960–1279) that followed was the first government to issue paper currency.