Chung-Tu

Chung-Tu was a city in China which was located in the Chin Empire, however that empire was invaded by Genghis Khan and the Mongol Empire in around 1210 and no longer existed in 1240. In 1240 near Kiev, the First Doctor met Ling and deduced that he was from Chung-Tu having recognised his accent. (PROSE: Bunker Soldiers)

Behind the scenes
The modern spelling of the city is Zhongdu.