A century after the Reformation, Lutheran Germany had sound doctrine but, to some, a cold church. Philipp Jakob Spener answered in 1675 with a short book, the Pia Desideria — 'pious desires' — calling for a renewal of heartfelt, practical Christianity within the Lutheran Church.
Pietism stressed personal conversion and the new birth, the devotional reading of Scripture in small gatherings, and a faith proven by love and good works. Under August Hermann Francke it built schools, orphanages, and a great center of mission and learning at Halle.
Pietism's reach was enormous. It shaped the Moravians, deeply influenced John Wesley and the Methodist revival, and fed the modern missionary movement. Wherever later Christianity emphasized the heart, the small group, and the new birth, Pietism's influence can be traced.