Nachman of Breslov (1772-1811), the great grandson of Israel Baal Shem Tov, was the founder of the Breslover Chasidic sect. 

Nachman contributed much to the doctrines of Chasidism. He taught that righteous leaders (Tzadickim) were mediators between God and people, and not miracle workers. Nachman required an unquestioning faith in God, and encouraged his followers to pray incessantly. Dancing and singing, joy and ecstasy, were part of worshipping God.  He preached a simple lifestyle that focused on spiritual, rather than material, well-being.