 In a paper from 1882, “Brief Description of the Algebra of Relatives”, reprinted in De Morgan 1966, he used these quantifiers to define operations on relations by means of operations on certain kind of coefficients. De Morgan gets credit for introducing the concept of relation, but Peirce is considered the true creator of the theory of relations (see, e.g., Tarski 1941: 73). However, Peirce did not develop this theory. As Calixto Badesa wrote, “the calculus of relatives was never to Peirce’s liking” (Badesa 2004: 32). He considered it too complicated because of the combination of class operations with relational ones. Instead, he preferred from 1885 onwards to develop a “general algebra” including quantifiers but no operation on relations. In this way, he arrived at an elementary and informal presentation of what is now called first-order logic (see Badesa 2004, loc. cit.).