Instructions: This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
Input: To the north of China proper, the nomadic Xiongnu chieftain Modu Chanyu (r. 209–174 BC) conquered various tribes inhabiting the eastern portion of the Eurasian Steppe. By the end of his reign, he controlled Manchuria, Mongolia, and the Tarim Basin, subjugating over twenty states east of Samarkand. Emperor Gaozu was troubled about the abundant Han-manufactured iron weapons traded to the Xiongnu along the northern borders, and he established a trade embargo against the group. Although the embargo was in place, the Xiongnu found traders willing to supply their needs. Chinese forces also mounted surprise attacks against Xiongnu who traded at the border markets. In retaliation, the Xiongnu invaded what is now Shanxi province, where they defeated the Han forces at Baideng in 200 BC. After negotiations, the heqin agreement in 198 BC nominally held the leaders of the Xiongnu and the Han as equal partners in a royal marriage alliance, but the Han were forced to send large amounts of tribute items such as silk clothes, food, and wine to the Xiongnu.
Output:
Who was the chieftain of the Xiongnu?