劉粲
It is not known when Liu Can was born. His family claimed ancestry from the ruling house of the Spring and Autumn period state Lu — specifically, from the nobleman Liu Xiahui. The traceable ancestry of Liu Can's included officials of Northern Wei, Sui Dynasty, and Tang Dynasty. Liu Can's grandfather Liu Qi (柳器) was a cousin of the famed official and calligraphy Liu Gongquan, and his father was named Liu Zhongzun (柳仲遵); neither Liu Qi nor Liu Zhongzun were listed with any official titles. (Liu Can's biography in the "Old Book of Tang" gave alternative names of Liu Gongqi (柳公器) and Liu Zun (柳遵) for Liu Can's grandfather and father, respectively.) Liu Can had at least two younger brothers, Liu Yu (柳瑀) and Liu Jian (柳瑊).