Han Wudi

Regnal years

One of Han Wudi's innovations was the practice of changing reign names after a number of years, as deemed auspicious or to commemorate some event. Thus, the practice for dating years during the reign of Wudi was represented by the n year of the [Reign Year Name] (where n stands for an ordinal integer) and "Reign Year Name" for the specific name of that regnal year. This practice was continued by later emperors until the Ming and Qing eras, whereby the emperors of the two dynasties used only one reign name for their entire reign (unless interrupted, as in the case of Emperor Yingzong of Ming).