The earliest appearance of cheese was in Poland in 5,500 BCE. Curiously enough, this is much before the word for it was invented, since Proto-Indo-European came around a thousand years later. Though etymologists are befuddled and bemused by the root of this word, the common theory is that it comes from the PIE word kwat, meaning "sour", due to the sourness of cheese resulting from fermentation (this word was picked up and kept by many Slavic languages as the name for a sour mineral-water-like drink, so they're basically drinking cheese). After about 4,000 years of being mangled beyond any recognition, the word reemerged in Latin, with its current definition, as caseus. If you've taken a foriegn language, this might sound familiar: it was also the forebear of the Irish, Italian, and Spanish words for cheese. This went into German as kajsus, and later appeared in Saxon as cese, another inexplicable mutilation of a word. In Old English, they added an h to make chese, and eventually, since everybody was mispronouncing it anyway, chese became cheese. The ancient root of "sour" still exists in some cheeses, but culinary technique now also gave us wonderful, sweet, and myriad cheeses of all kinds.
Adam Aleksic, a rising sophomore studying linguistics and government at Harvard University, has been described as the internet's sixth most famous etymologist. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.