By the early fifth century the Celestial Masters tradition Zhang Daoling had founded nearly three centuries earlier had spread widely and, its critics said, degenerated: hereditary clerical office, fee-for-ritual practice and syncretic accretions that reformers considered corruptions of the original revelation. Kou Qianzhi announced in 415 that Laozi himself had appeared to him on Mount Song and commissioned a purge, delivering a new code of purified liturgy and clerical discipline meant to restore the tradition's original discipline and strip out what he judged its abuses.
The reform might have stayed a local monastic matter had Kou Qianzhi not carried it to the Northern Wei court, where Emperor Taiwu and his chancellor Cui Hao were receptive to a purified state Daoism that could anchor the young dynasty's legitimacy. In 440 the emperor adopted a new reign title, Taiping Zhenjun, True Lord of Great Peace, taken directly from Kou Qianzhi's revealed title for the emperor, and Daoism was declared the state religion. The elevation had a dark second half: in 446, amid suspicion of a Buddhist monastery's involvement in a rebellion, Taiwu ordered a severe persecution of Buddhism across the realm, monasteries destroyed and monks killed or laicized. Sources disagree on how much Kou Qianzhi himself pushed for this outcome against the more zealous Cui Hao, and several record him arguing, without success, for restraint once the persecution began. He died two years later, and much of the anti-Buddhist policy was reversed within a decade of his death, but the precedent his revelation set, a Daoist reform movement entering the machinery of the state directly through the ruler's own reign title, had no real precedent before him.