ALGOL 60 combined an international language-design process with block structure, lexical scope, recursive procedures and a formal syntax notation that influenced generations of later programming languages.
Before leading FORTRAN, John Backus built Speedcoding for the IBM 701, an interpretive system that made floating-point scientific programming easier while exposing the performance cost of abstraction.
FORTRAN did more than introduce convenient mathematical notation. Its compiler proved that a high-level language could produce code efficient enough for serious scientific work.