 In spite of the six-year interval between Frege’s Begriffsschrift (1879) and Peirce’s quantification theory in 1885, credit has been given to both logicians. We call them both the founders of modern logic, since Peirce was not aware of Frege’s work on the topic. Also, it should be noted that Frege presented a logical system equipped with axioms and rules, which was not pursued in Peirce’s work.