The Ancient History of Soap making
Since antiquity the Sumerians had documented the use of soap solutions. They discovered that when it rainedd on the leftover remains of various feasts and sacrifices, the potash, rainwater and animal fat reacted to produce a latherous substance called soap. By 3000 BC the babylonians first used a slurry of ashes and water to remove grease from raw wool so that it could be dyed. Babylonian priests purified themselves before sacred ceremonies in this slippery alkali slurry of potash and fat, which reacted with grease and oils to dissolve it to form a latherous creamy soap. The Babylonians, realising this, proceeded to make soap solutions directly by boiling fats and oils in the alkali before using it for cleaning. Specific directions for making different kinds of soap solution have been found on cuneiform tablets all over the alluvial plains of Mesopatamia. In the Old testament soap is mentioned twice " thou wash thee with nitre, and take thee much soap, yet thine iniquity is marked.." says the book of Jeremiah, and the book of Malachi states "He is like a refiner's fire, like a fuller's soap"
H. W. Salzberg, From Caveman to Chemist, American Chemical Society, Washington DC, 1991