Philipp Jakob Spener was the founder of the Lutheran pietistic movement; his letters are an essential source for research into the Early Modern Age, not only in terms of church history, but also regarding cultural history and the history of ideas.
The edited 'Letters from the Berlin period 1691-1705' shed light on Spener's period as provost at the Church St. Nikolai in Berlin. Letters from the same period are published in 'Briefwechsel mit Adam Rechenberg' from volume 3 and in 'Briefwechsel mit August Hermann Francke'.
Volume 1 contains 190 letters from the years 1691-1693, in which Spener described the circumstances of his change from the position as the court preacher in Dresden to Berlin as Lutheran provost under reformed sovereignty. The consequences of the pietistic disturbances in Leipzig and the horrors of the War of the Palatinate Succession (Nine Years' War) are reflected in his letters. The Wolfenbüttel Edict against Pietism renewed the accusation of the emergence of a new sect. Chiliastic positions and the phenomenon of new revelations were categorised and commented by Spener. Important literary debates began.