> A monad is a concept that belongs to a branch of mathematics called category theory, where it was introduced in the 1960s. No. [1] [1] General Theory of Nat

> A monad is a concept that belongs to a branch of mathematics called category theory, where it was introduced in the 1960s. No. [1] [1] General Theory of Natural Equivalences, Mac Lane and Eilenberg, 1945. https://www.ams.org/journals/tran/1945-058-00/S0002-9947-1945-0013131-6/S0002-9947-1945-0013131-6.pdf https://www.ams.org/journals/tran/1945-058-00/S0002-9947-194...