Female shamans played an important role in this tradition, which was particularly strong in the southern state of Chu. Early Taoist movements developed their own institution in contrast to shamanism but absorbed basic shamanic elements. Shamans revealed basic texts of Taoism from early times down to at least the 20th century. Institutional orders of Taoism evolved in various strains that in more recent times are conventionally grouped into two main branches: Quanzhen Taoism and Zhengyi Taoism. After Lao Tzu and Zhuangzi, the literature of Taoism grew steadily and was compiled in form of a canon—the Tao Tsang—which was published at the behest of the emperor. Throughout Chinese history, Taoism was nominated several times as a state religion. After the 17th century, however, it fell from favor.