Cai Lun, formerly romanized as Ts'ai Lun, courtesy name Jingzhong, was a Chinese inventor and eunuch court official of the Eastern Han dynasty. He is traditionally regarded as the inventor of paper and the modern papermaking process, as he originated paper in its modern form.

Paper is a thin nonwoven material traditionally made from a combination of milled plant and textile fibres. It is primarily used for writing, artwork, and packaging; it is commonly white. The first papermaking process was documented in China during the Eastern Han period (25–220 AD) traditionally attributed to the court official Cai Lun. During the 8th century, Chinese papermaking spread to the Islamic world, where pulp mills and paper mills were used for papermaking and money making. By the 11th century, papermaking was brought to Europe. By the 13th century, papermaking was refined with paper mills utilizing waterwheels in Spain. Later European improvements to the papermaking process came in the 19th century with the invention of wood-based papers.