Zhang Guolao (張果老) was a Taoist occultist, alchemist and hermit who lived on Zhongtiao Mountain in Hengzhou during the Tang Dynasty. Fond of wine, Zhang made his own from herbs. He was also a master of qigong (氣功).
Known for his eccentricity, Zhang was apparently fond of making himself invisible, causing flowers to wilt by pointing at them and even catching birds in midflight.
He is usually depicted riding a white donkey or mule, which he sits on facing its rear. It is said that, at the end of any journey made, Zhang Guolao would fold up his donkey and place it in his pocket or a small receptacle. When he wished to ride once more, Zhangwould then spit water at it and it would then gain its size and form again.
Although shown as an elderly man (lao 老 means old), Zhang is the patron deity of young families and the bringer of male heirs.