The system of binomial nomenclature, in which every species is described by two names--first genus, then species--was created by Carolus Linnaeus. He named as many species as he could, and also came up with a branching division of Kingdom, Phylum, Class, Order, Family, Genus, Species (KPCOFGS). He worked on this from the 1730s to his death in the 1770s. His naming of and division of species was so excellent and made so much sense that it came to be adopted by all scientists, eventually. Prior to this, there was a much less systematic way of naming animals, where you might use 4 names, or just one name, or a combination. The two name system just worked really well. And the KPCOFGS system also was really helpful in figuring out where various living htings fit in the general scheme of things. This was a time when many new species were being encountered and described by European scientists, and Linnaeus fit each of them into his system, which set the stage for everyone to start using it whenever anyone talked about any species. There have been adjustments of the names over the centuries--for example, he originally put humans in their own family, separate from other species, but now we are in a family with chimps, gorillas, and orangutans. He also put into the system creatures which we would now consider to be mythological and have removed from classification. He chose the names of species to be of Latin or Greek origin, as those were the languages of science at that time. When new species are discovered, we still use Latin or Greek language for them.