Miguel de Molinos was the main inspiration. But Madame Guyon - particularly through her book "A Short and Easy Method of Prayer" - helped popularize his approach.
Her high-profile supporter was Archbishop Fenelon. All three were targetted by the Church hierarchy. The history of Catholicism would have been radically different if their ideas had been treated with more respect. Jeanne-Marie Bouvier de la Motte-Guyon