Soap is a wonderful thing. Most folks are so used to simply choosing a brand from the supermarket shelf; they never think about whats in it or how its made or whether its even good for them. Nevertheless, because we use it every day on our bodies, its worth knowing a little bit about how soap is made and where it comes from. When 
you think about it, the common act of washing our hands has revolutionized history.Soap is made from vegetable or animal fats and oils, mixed with a caustic alkali such as sodium hydroxide (lye) or potassium hydroxide (potash), which initiates a chemical reaction called saponification.
The traditional method of producing potash was to steep wood ashes in water.Our world would not exist, if mankind had not at some point begun to bathe. When asked, most folks cannot define the word soap. It's something we take for granted. But what is it?
Soap does not occur naturally, but the process of creating it is so simple that its discovery probably occurred long before the first villages and towns came into being. There is a legend, repeated endlessly in soap making books and websites, which tells of a certain hill in Rome called Mount Sapo.
There was supposedly a temple on the top of this hill where animals were sacrificed in the fire, and the fats and ashes ran downhill into a river.
Women doing their laundry discovered that their clothes became cleaner when they washed them at the foot of Mt. Sapo. It's an attractive story, but it probably never happened. No one knows anything about a hill called Mt. Sapo, by a river or anywhere else. Something like this may have occurred at some distant place and time, but even so it certainly does not mark the first discovery of soap.
Soap was probably first discovered when fire pits, used season after season by bands of hunters, were rained on.
ie animal fats from many kills would have dripped down into the ashes, and the rains would have soaked the ashes to create a crude form of lye. Yes, the cave men probably knew how to make and use soap! Soap has been found in excavations at ancient Babylon, dating from 2800 BC. An ancient medical papyrus from Egypt describes the healing properties of vegetable oils mixed with alkali salts.
Interestingly, the idea of using soap for personal hygiene and cleansing seems to have come along fairly late. It was used mainly for washing wool and cleaning laundry long before anyone thought of using it to clean themselves. Ashes and animal fat were (and still are) smeared on the body by primitive peoples to create a startling or distinctive appearance. Stripes or patches of different colors would also have been useful in the hunt, functioning exactly like a tiger's stripes or the camouflage worn by hunters today. Once colored pigments were added, both war paint and cosmetics came into being. However, a simple mix of fat and ashes is not soap, but a precursor.
For oils to saponify , ashes must be converted to lye. It was this process that must have been most elusive to our earliest ancestors. Even so, there is abundant evidence that the properties of caustic alkali salts were appreciated at a very early time. Strictly speaking, ashes steeped in water do not create lye, but potash. Lye is a caustic sodium salt which is made from brine. The process for creating this chemical on an industrial scale was invented in the 19th century, and had a huge impact on the soap industry. Prior to that time, most soap was made with potash or a refined form call pearlash. Potash is a caustic salt of potassium rather than sodium. It is still used today in the production of liquid soaps. The addition of table salt or sodium chloride to harden soap was known at least as early as the Roman era, and in various locations natural deposits of caustic alkali were known to exist. Nevertheless, the use of sodium salts in the form of lye to create hard soaps was a late development.
Many other ancient peoples also discovered the usefulness of soap. The ancient Romans, Celts, Hebrews, Phoenicians and Egyptians all knew how to saponify various fats and oils. There is supposedly a preserved soap factory at Pompeii, complete with finished, modern-looking bars, although more recent study of the site has thrown doubt on what this space may actually have been used for.
Following the collapse of the Roman Empire, much of Europe forgot how to make soap. Bathing remained popular, but it was often considered risque or even a little sacrilegious. St. Jerome is supposed to have said that having been washed clean in Christ, it was not necessary to bathe again. It was a time when the Church held the great masses of people in an iron grip of ignorance and poverty. The filth and unsanitary conditions of medieval Europe contributed to plagues and all kinds of illness. Still, there were soap-making centers in Italy and France as early as the 9th century.
Personal cleanliness did not gain mass popularity in Europe until the 17th century. Eventually, though, soapmaking industries did emerge in Italy and France. Vegetable oils and purified animal fats (lard and tallow) were blended with costly scents and colorants, as well as various kinds of botanical essences. In the 14th century the French emerged as the makers of the finest soaps, using imported oils instead of tallow. In England, where soapmaking had long been a byproduct of the chandler's trade, soapmaking had yet to come into its own. Soapmakers who tried to specialize found themselves so heavily taxed that it was difficult to stay in business.
The Muslims- who occupied Spain and North Africa during the height of the Islamic empire maintained a high level of cleanliness. Their cities were clean, beautiful and well-lit, and their universities attracted scholars from around the world. In science, art, medicine, philosophy, and many of the basic aspects of civilization, the Muslims provided the foundation which eventually lifted Europe up from the Dark Ages to the Renaissance.
Throughout the Muslim world, soap was made from olive, palm, laurel and other oils. In Spain, the region called Castilla is remembered for a mild soap made from pure olive oil. True castile soap, made from olive oil or olive pomace oil (the oil drained and pressed from the leftover material from the olive press), is a soft white bar that is extremely mild. It doesn't lather very well, though, and soap makers experimented with adding other oils.
Advances in shipping and exploration brought new materials to the marketplace, and soapmakers learned that coconut oil produces a luxurious lather; while palm oil stabilizes the mixture and produces a hard, long-lasting bar. Castor oil attracts moisture to the skin and adds lather as well. Many other oils are used for their healing and conditioning properties.
Soap was heavily taxed as a luxury item well into the 19th century, especially by the British. Once the taxes were lifted, soap became available to ordinary people, and sanitary conditions improved. Commercial soap making in America dates from 1608, when soap makers arrived from England aboard the first ship to follow the Mayflower.