As projectleader with IBM John Backus developed in the early 1950's with his team: Fortran - Formula Translator. Fortran was released in 1954. The first high level programming language. This language is most widely used in physics and engineering.
He was also responsible for the Backus-Naur Form (or BNF), a standard notation which can be used to decribe the sytanx of a computer language in a formal and unambiguous way.