The first evidence of soap making dates from the ancient world, around 2800 BC Archaeologists found clay cylinders left by the Mesopotamian civilization that had been covered with a soap-like substance inside. Once the archeologists deciphered the inscriptions on the cylinders, they were surprised to find a description of fats being boiled with ashes – the basic method of making soap. Intriguingly, these early cylinders did not describe what this soap-like substance was used for, and so archeologists are left to guess.
As in Mesopotamia, so too did archaeologists find Pharaonic artifacts that attest to ways to make soap. A medical text written on papyrus, the Ebers Papyrus dating to 1500, outlines a method to combine animal and vegetable fats with alkaline salts. The resulting soap-like material could have been used for bathing, or as a topical treatment for skin diseases. Biblical evidences suggest that a third ancient civilization, the Israelites, knew how to mix ashes and vegetable oils to produce something a great deal like hair gel. By the second century AD, Alexandria's famous physician, Galens, recommended that his patients use soap as a topical ointment, as well as to keep clean.
The Mediterranean civilizations – Greece and Rome – preferred to wash without soap, but they learned about soap form the people they colonized. Pompeii's ruins included a soap factory, complete with a batch of soap. Both Greeks and Romans cleaned their bodies by rubbing them with oil, and then scrapping the oil off with metal instruments or pumice stones. Ancient Germans and the Gauls made their own soap out from ashes mixed with animal fat, and they used it to decorate their hair.
Europeans started to use soap to clean their bodies in the Renaissance, and once soap came to be widely used for personal cleanliness, its chemical formula did not change much. The soap made by the American colonists (that you can watch made at any open-air museum) is much the same soap that has been made since the Renaissance. The person making soap would collect lye by dripping water through wood ashes, and then mix the resulting lye with animal or vegetable fat to make soap.
Source by Sarah Freeland