The functional programming languages, such as Haskell, Lisp, Miranda, Scheme and SML, are based on Alonzo Church's λ-calculus.  λ-calculus, Turing machines and combinatorial logic are all equivalent in that they can compute exactly the same things but since the λ-calculus is the most like a programming language it has a good claim to being the prototype programming language.

A. Church, The Calculi of Lambda conversion, Princeton Univ. Press, Annals of Mathematical Studies, 1941.