Radical Pietism refers to a movement within Protestantism, lasting from the late 17th century to the mid 18th century and later, which emphasized the need for a "religion of the heart" instead of the head, and was characterized by ethical purity, inward devotion, charity, asceticism, and even mysticism. Leadership was empathetic to adherents instead of being strident loyalists to sacramentalism. Many of the Radical Pietists were influenced by the writings of Jakob Böhme, Gottfried Arnold, and Philipp Jakob Spener, among others.