The unification of China in 221 BC, under the First Emperor Qin Shi Huang, marked the beginning of Imperial China. To consolidate his rule, Qin Shi Huang enacted various reforms. First, centralization of power was established, with judicial, executive and military powers lying in the hands of the emperor. Second, the county system was enforced to govern administrative regions throughout the country. Third, the forms of written characters were unified and standardized. Fourth, currency was standardized to “banliangqian” (coins weighing 2.8-8.1g); and measurements of length, weight and volume were unified. Other measures included construction of expressways, application of new laws, and many others. However, the Qin Dynasty lasted only 15 years before it was replaced by the Han Dynasty. The reasons for its decline might be traced in its repressive measures, ruthless law codes, and continual military expeditions.