How It All Got Started
It all began with a linguistics professor who gave a series of lectures on language at the University of Geneva between 1906 and 1911. He had a very bushy mustache, studied more dead languages than most people know exist, and was named Ferdinand de Saussure. He died in 1915, before (gasp!) he'd had a chance to compile his revolutionary ideas on the structure of language into a book. But Saussure's students came to the rescue: after he died a couple of them went through mountains of lecture notes and compiled those into a book that was published in 1916 as Course in General Linguistics. Snoopy? Maybe. But if they hadn't poked around in his stuff the theory of structuralism would never have gotten off the ground.
That book would be picked up by other linguists, most importantly a Russian named Roman Jakobson and his buddies in the Prague School of linguists. They built on Saussure's theory to develop what came to be known as the field of "structural linguistics." So, Saussure's structuralism was still confined to the world of linguistics.
But then, the 1940s happened, and that's when theorists and scholars from other fields started paying attention. Hey, they said. This stuff about language and structure is pretty interesting. And you know what? It kind of applies to everything. We can analyze familial patterns in terms of language, and can even give it the fancy term "kinship." We can analyze fashion trends in terms of language. We can even analyze what people eat in terms of language.
From there, structuralism exploded. Anthropologists, philosophers, literary theorists, psychologists, all began applying structuralist principles in their fields, and structuralist theories soon made their way into a range of disciplines in the humanities and social sciences.