The roles of women in Taoism (ˈdaʊɪzəm, ˈtaʊ-) (also spelled "Daoism" ˈdaʊ-) have differed from the traditional patriarchy over women in ancient and imperial China. Chinese women had special importance in some Taoist schools that recognized their transcendental abilities to communicate with deities, who frequently granted women with revealed texts and scriptures. Women first came to prominence in the Highest Clarity School, which was founded in the 4th century by a woman, Wei Huacun. The Tang dynasty (618–907) was a highpoint for the importance of Daoist women, when one-third of the Shangqing clergy were women, including many aristocratic Taoist nuns. The number of Taoist women decreased until the 12th century when the Complete Perfection School, which ordained Sun Bu'er as the only woman among its original disciples, put women in positions of power. In the 18th and 19th centuries, women Taoists practiced and discussed nüdan (女丹, "women's neidan inner alchemy"), involving gender-specific practices of breath meditation and visualization. Furthermore, Taoist divinities and cults have long traditions in China, for example, the Queen Mother of the West, the patron of xian immortality, He Xiangu, one of the Eight Immortals, and Mazu, the protectress of sailors and fishermen. Since organized Taoism began in the late Han dynasty (202 BCE – 220 CE), women have been active in different schools, which gave them diverse names. In the Tianshi Dao (Way of the Celestial Masters), they were called nüshi (女士 or 女師, "female masters") when married to a Master, or nüguan (女官, "female officers") when among chosen zhongmin (種民, "seed people"). In the Shangqing (Highest Clarity) School, Taoist nuns were most often solitary practitioners, and called nü daoshi (女道士, "female Taoists" or "female Taoist masters") or nüguan (女冠, "female hats", describing a distinctive ritual headdress) in the Song dynasty. The Quanzhen (Complete Perfection) School uses daogu (道姑, "ladies of the Dao") in reference to both convent nuns and devout laity.