If one is puzzled by the fact that the once great Qin Empire collapsed only fifteen years after it unified China, he is then bound to wonder why the once seemingly weak Han Empire lasted so long. The 411 years of the Han Dynasty, divided nearly equally into two halves by the reign (dynasty) of the usurper Wang Mang from AD 9 to 23, constituted a period of paramount importance in Chinese history and in the process of China’s formation as a nation. This pattern of historical development that a short-lived dynasty was taken over by a long-lasting dynasty in which many of the former’s inventions went through significant modifications is itself very interesting – it was repeated by the transition from Sui to the Tang Empire (AD 618–907). The Han Dynasty was both militant and culturally inspired, and its remarkable success instilled in China a deep sense of legitimacy granted to the imperial bureaucratic state backed by Confucian ideology. Particularly what happened between Han and the Xiongnu Empire in the second to first century BC was the struggle between two great empires using their full strength that occupied an important position in the world’s military history. The victory the Han Empire was able to consolidate through a series of difficult engagements led it to pursue expansionist goals in regions far from the Han borders. Consequently the Han Dynasty was also a time of great geographical discovery as Han envoys reached nations and tribes in central and western Asia, where the West and the East first truly entered each other’s sight. The discussion below of the Han Dynasty is divided into three parts: Chapter 12 reviews the political and military development under the Han Empire; Chapter 13 will discuss the internal organization and social orders of the Han Empire; the final chapter will analyze Han intellectual trends and highlight the splendors of Han material culture.