The influenza pandemic of 1918 killed Maori at something like seven times the rate it killed Pakeha. It was in that season, on his farm near Whanganui, that Ratana reported a vision: cloud coming in off the sea, a voice naming him as the mouthpiece, and an instruction to unite the Maori people and to turn them to God alone.
What followed was not what a farmer with a vision would ordinarily produce. People came to be healed, first in dozens and then in thousands, camping around the farm until a township grew there. Contemporary newspapers reported the crowds; the Anglican and Methodist churches, which had expected to absorb the movement, found they could not.
The teaching had a hard edge that is easy to miss under the healings. Ratana attacked the use of charms, of tohunga practice and of anything he regarded as an intermediary, and he pressed a strict monotheism expressed as the Father, the Son, the Holy Spirit and the faithful angels. His own title, the mangai, means mouthpiece: he claimed to speak for God rather than to possess power himself, and he consistently deflected requests to heal onto faith rather than onto his own hands.
By 1921 the gatherings were enormous. In 1925 the movement was constituted as a church, and the healing years gave way to an institution with a creed, a register of adherents and a settlement of its own.