The eight immortals are the eight Taoist immortals widely spread in Chinese folklore.

Zhang Guo is always the oldest fairy among the eight immortals, named Zhang Guo. Because he is the oldest among the eight immortals, people respectfully call him Zhang Guo Lao. In history, Zhang Guo was actually a man. In the records of Emperor Xuanzong of Tang Dynasty's imperial seal of immortal Zhang Guo during the Kaiyuan period of Tang Dynasty, it was recorded as Guangzong people in Xingzhou (now from zhangguzhai village, Guangzong County, Hebei Province). The new and old Tang books have been handed down. When Wu Zetian was in seclusion, Zhang Guo lived in Zhongtiao Mountain. At that time, people said that he had the secret of longevity. He claimed that he was hundreds of years old. Wu Zetian sent messengers to summon him. Zhang Guo pretended not to die. In the 21st year of Kaiyuan of Xuanzong of the Tang Dynasty, Wei Ji, the governor of Hengzhou, played his anecdote to the emperor. Xuanzong called it, and Zhang Guo pretended to be dead again. He was out of breath for a long time before he woke up, and the messenger dared not advance. Hearing this, Xuanzong sent Xu Qiao to invite him again, and Zhang Guo had to go to Beijing. It is said that Emperor Xuanzong of the Tang Dynasty doubted his rumors. He once asked Xing Hepu, who was good at calculating the good and evil of life, to give Zhang fortune telling, but Xing was ignorant of Zhang's Jiazi; There was also a Taoist night light who was good at seeing ghosts. Xuanzong asked him to see Zhang Guo, but he asked, where is Zhang Guo? he couldn't see it opposite. According to the Taiping Guangji, Zhang Guolao claimed to be from the time of Emperor Yao. Xuanzong of the Tang Dynasty asked the magician ye fashan about Zhang's origin. Ye fashan said, I dare not say, but I will die when I say it. Later, he said, Zhang Guo is a white bat spirit at the beginning of chaos. After that, he fell to the ground and died. After Xuanzong pleaded for mercy, Zhang Guo saved him.

It is said that old Zhang Guo often carries a moral tube, rides a white donkey upside down, travels around, preaches and sings Taoist feelings and persuades people. Later, the famous folk saying riding a donkey to see a libretto came from this. His white donkey travels thousands of miles a day, folds like paper at night and puts it in a box; When riding during the day, spray it with water in your mouth, and it will return to a donkey. Later generations wrote a poem: there are no more people in the world than this old man. It's not riding a donkey upside down. Look back.