<P> On occasion, the father of the ascended emperor was still alive . Such an emperor was titled the Tai Shang Huang (太上皇), the "Grand Imperial Sire". The practice was initiated by the First Emperor, who gave the title as a posthumous name to his own father . Liu Bang, who established the Han dynasty, was the first to become emperor while his father yet lived . It was said he granted the title during his father's life because he would not be bowed to by his own father, a commoner . </P> <P> Owing to political fragmentation, over the centuries, it has not been uncommon to have numerous claimants to the title of "Emperor of All China". The Chinese political concept of the Mandate of Heaven essentially legitimized those claimants who emerged victorious . The proper list was considered those made by the official dynastic histories; the compilation of a history of the preceding dynasty was considered one of the hallmarks of legitimacy, along with symbols such as the Nine Ding or the Heirloom Seal of the Realm . As with the First Emperor, it was very common also to retroactively grant posthumous titles to the ancestors of the victors; even in Chinese historiography, however, such grants were not considered to elevate emperors prior to the successful declaration of a new dynasty . </P> <P> The Yuan and Qing dynasties were founded by successful invaders; as part of their rule over China, however, they also went through the rituals of formally declaring a new dynasty and taking on the Chinese title of Huangdi, in addition to the titles of their respective people . Thus, Kublai Khan was simultaneously Khagan of the Mongols and Emperor of China . </P> <P> On one count, from the Qin dynasty to the Qing dynasty, there were 557 emperors including the rulers of minor states . Some, such as Li Zicheng, Huang Chao, and Yuan Shu, declared themselves the Emperors, Son of Heaven and founded their own empires as a rival government to challenge the legitimacy of and overthrow the existing Emperor . Among the most famous emperors were Qin Shi Huang of the Qin dynasty, the Emperors Gaozu and Wu of the Han dynasty, Emperor Taizong of the Tang dynasty, Kublai Khan of the Yuan dynasty, the Hongwu Emperor of the Ming dynasty, and the Kangxi Emperor of the Qing dynasty . </P>

How did mongol leaders change chinas government during the yuan dynasty