Laoshang (or Jizhu), son of the Xiongnu chieftain Modu Chanyu, killed the king of the Yuezhi around 162 BC, and in accordance with their tradition, "made a drinking cup out of his skull".[4] According to the biography of the envoy Zhang Qian in Han shu,[5] the drinking cup made from the skull of the Yuezhi king was later used when the Xiongnu concluded a treaty with two Han ambassadors during the reign of Emperor Yuan of Han (49-33 BC). To seal the convention, the Chinese ambassadors drank blood from the skull cup with the Xiongnu chiefs.