Who invented soap?

Although the Romans are most often credited with the discovery of soap around 1000 B.C. - directions for soapmaking have been found on Sumerian clay tablets dating around 2500 B.C. Legend says that a mixture of animal fat and wood ash from a sacrifice somehow made it into the Tiber River on Sapo Hill where women were doing laundry. They discovered that the clothes came cleaner because of this substance. Our modern word "soap" was derived from "Sapo" from where this solution was believed to originate.

It is questionable whether the people of the time were conscious that soap was being produced. The recipes don't mention that soap is produced, and the soap is never actually separated from the solution. In fact, the first concrete evidence of knowledgeable soapmaking is found in ancient Rome. The ruins at Pompeii revealed a soap factory with finished bars. However Romans, famous for their public baths during this time, did not use the soap because it was too harsh for the skin and used only for clothing.

It wasn't until the 18th century when bathing came into fashion again that soapmaking techniques began to resurface. Prior to that, bathing was in disfavor due to superstitions that it was dangerous and unsanitary. A new demand for "domesticated soaps" (soaps used for bathing) resulted in new discoveries in the soapmaking process. Soap was produced throughout Europe and ingredients began to differ based on the region. Colonial America, however, was the exception. Soap companies did not begin to appear until the early 19th century.