query: How long did the Qin dynasty last?
passage: Qin dynasty
The Qin dynasty (Chinese:秦朝; pinyin:Qíncháo; Wade–Giles:Chʻin²-chʻao²) was the first dynasty of Imperial China,[2] lasting from 221 to 206 BC. Named for its heartland in Qin state (modern Gansu and Shaanxi), the dynasty was founded by Qin Shi Huang, the First Emperor of Qin. The strength of the Qin state was greatly increased by the Legalist reforms of Shang Yang in the fourth century BC, during the Warring States period. In the mid and late third century BC, the Qin state carried out a series of swift conquests, first ending the powerless Zhou dynasty, and eventually conquering the other six of the Seven Warring States. Its 15 years was the shortest major dynasty in Chinese history, consisting of only two emperors, but inaugurated an imperial system that lasted, with interruption and adaptation, until 1912 CE.
passage: Duke Wu of Qin
Duke Wu of Qin (, died 678 BC) was from 697 to 678 BC the tenth ruler of the Zhou Dynasty state of Qin that eventually united China to become the Qin Dynasty. His ancestral name was Ying (), and Duke Wu was his posthumous title.