Generative grammar was defined by Noam Chomsky around 1955. He was more or less alone, claiming that there are generative mechanisms in grammar.
Frieder Nake, Frieder Nake on “Machinic” Miracles
Chomsky showed how the concept of grammar could create rules that allow you to automatically generate correct sentences. He must have had a wonderful, looking-into-the-future brain by reducing linguistics to its very basics.
Frieder Nake, Frieder Nake on “Machinic” Miracles