The earliest-known use of soap dates back to the ancient Babylonians, who made soap as early as 2800 B.C. Clay containers from that era have been found inscribed with a recipe for soap made from animal fats combined with wood ash and water.
Soap was well-known throughout the ancient world. The ancient Egyptians made soap as early as 1550 B.C. by combining animal and vegetable fats with alkali salts. An entire soap-making factory was discovered in the ruins of Pompeii. Using soap for personal hygiene did not become prevalent until the late Roman Empire. Prior to that, it was used primarily for cleaning textile fibers prior to weaving and by physicians to treat skin disease.