  Leibniz’s impact on the emergence of modern logic, be it mathematical, algebraic, algorithmic or symbolic logic, is an important topic for understanding the emergence and development of the logic predominant today (on Leibniz’s influence and reception cf. Heinekamp (ed.) 1986; on his influence in logic cf. Peckhaus 1997). However, the question whether Leibniz had any influence at all, or whether his ideas were rather not more than ingenious anticipations of later developments, is still disputed. The significance of this problem can be shown by referring to Louis Couturat, who claimed that in respect to the logical calculus Leibniz already had all the principles of much more recent logical systems of the algebra of logic (George Boole, Ernst Schröder) and was even more advanced in some points (Couturat 1901, 386). But did early “modern” logicians like Boole, Schröder, or Frege have any knowledge of Leibnizian logic, i.e., could Leibniz have had any influence on these pioneers of modern logic?