The Qin Dynasty was a dynasty in China that flourished around 221 BC. The emperor during the Qin dynasty was Qin Shihuang.
History
In 221 BC, the Eleventh Doctor and Amy Pond visited China to leave a message for River Song on a vase. To write the message, the Doctor used his psychic paper to convince ancient Chinese potters that he had special permission from the emperor. The message was the expression, "Youza", written in period Chinese script. (TV: The Angels Take Manhattan)
One of the ships used by the Eternals in their contest for Enlightenment was a Chinese ship crewed by Chinese sailors from the Qin Dynasty. (TV: Enlightenment)