Vinegar was probably discovered when the first cask of wine turned sour. The French origin of the word 'vinegar' is 'vinagre', which means, literally, sour wine.
Cleopatra dissolved some pearls in vinegar to prove she could consume a fortune in a single meal.
Mother of Vinegar is the stringy, slimy substance composed of yeast cells and various bacteria that forms on the surface of fermenting liquids, turning it into vinegar. It is removed once the process is completed. After opening a bottle of vinegar, you may notice mother beginning to form. It is not harmful or spoiled. Filter it out and use it to make your own vinegar from wine or cider.