 This [Schröder’s Vorlesungen über die Algebra der Logik was the result of his learning modern quantification from Frege’s Begriffsschrift] is a simple and plausible answer, but it is false. Schröder never claimed any priority for his quantification theory, but he did not take it from Frege. Schröder himself gives the credit for his use of \(\Sigma\) and \(\Pi\) to Charles S. Peirce and Peirce’s student Oscar Howard Mitchell (Schröder 1891, 120–121). (Peckhaus 2004: 12) 