The Yuan dynasty before them had been part of the Mongol Empire started by Genghis Khan. Its emperors had been Mongolian people, but most of China was Han Chinese. To keep their power, the Yuan used a Chinese kind of government of Three Departments and Six Ministries, with imperial examinations. Their laws gave special powers to Mongolian people, though, with other people from other countries ("Semu") placed second, northern Chinese third, and southern Chinese last. They were especially nice to Tibetan Buddhists and gave many important jobs to Muslims, although they also made Muslims break some rules and eat like Mongolians. Some Muslims were angry and started to fight the Yuan. Many people began to fight after the 1340s. The Black Death killed many people and the government did not keep up the work needed to stop the Yellow River from killing people when it flooded. The Red Turbans began fighting in 1351 and its best leader Zhu Yuanzhang made the Yuan emperor Toghun Temür run away from the capital city Khanbaliq (now inside Beijing) in 1368.