汉光武帝
The details of the life of the historical figure Zhang Ling are obscure; most of the information about him comes from later scripture and hagiography. According to these, Zhang traced his ancestral home to Feng County, Jiangsu, and was said to be a descendant of Zhang Liang. He was born in the tenth year of the "Jianwu" era during the reign of Emperor Guangwu of Han. He started reading the "Tao Te Ching" at a young age and studied in the Taixue (Imperial Academy) before. He served as a magistrate in Jiangzhou, Ba Commandery (present-day Chongqing) during the reign of Emperor Ming of Han.