Soaps have been used since antiquity. The earliest evidence of soap like materials dates back to 2800BC in Ancient Babylon. Inscriptions indicate that fats were boiled with ashes to produce the forerunner of modern soap. General use of soap goes back about 1000 years & the basic recipe remains unchanged Fats or oils plus Sodium Hydroxide Caustic soda produces a hard soap fats or oils plus Potassium Hydroxide Caustic potash produces a soft soap. Many current soaps are called syndet bars