Liu Zhen (simplified Chinese: 刘贞; traditional Chinese: 劉貞; pinyin: Liú Zhēn) was the son of Liu Sheng, and the grandson of Emperor Jing of Han. According to the Romance of the Three Kingdoms, Liu Zhen was granted the title of Ting Marquis of Lucheng (陆城亭侯) by the Emperor Wu of Han. In the Han Dynasty, a Marquis was expected to pay an annual tribute of gold to the emperor, which was to be used toward the ritual sacrifices to the gods and ancestors. Failure to pay this tribute was considered to be an offense meriting the stripping of one's noble rank. Liu Zhen failed to pay the tribute, and was thus stripped of his Marquis title. His family remained in Zhuo County at least until the time of Liu Bei, his descendant who became the ruler of Shu Han in the Three Kingdoms period.
More Detail: http://en.wikipedia.org/wiki/Liu_Zhen_(Han_Dynasty)