The History of Soap

Early History

Soapnut Tree (Reeta / Sapindus tree)
The earliest known use of a natural soap-like substance was the powder of the Reeta(Sapindus) nut, which was used by Indians since antiquity. Hindus in India were obliged to bathe at least once a day, every morning, in accordance with Ayurveda. Evidence of manufactured soap use are Babylonian clay cylinders dating from 2800 BC containing a soap-like substance. A formula for soap consisting of water, alkali and cassia oil was written on a Babylonian clay tablet around 2200 BC.
The Ebers papyrus (Egypt, 1550 BC) indicates that ancient Egyptians bathed regularly and combined animal and vegetable oils with alkaline salts to create a soap-like substance. Egyptian documents mention that a soap-like substance was used in the preparation of wool for weaving.

Roman History
It is commonly reported that a soap factory with bars of scented soap was found in the ruins of Pompeii (79 AD). However, this has proved to be a misinterpretation of the survival of some soapy mineral substance, [citation needed] probably soapstone at the Fullonica where it was used for dressing recently cleansed textiles. Unfortunately this error has been repeated widely and can be found in otherwise reputable texts on soap history. The ancient Romans were generally ignorant of soap's detergent properties, and made use of the strigil to scrape dirt and sweat from the body. The word "soap" (Latin sapo) appears first in a European language in Pliny the Elder's Historia Naturalis, which discusses the manufacture of soap from tallow and ashes, but the only use he mentions for it is as a pomade for hair; he mentions rather disapprovingly that among the Gauls and Germans men are likelier to use it than women.[1]
A story encountered in some places claims that soap takes its name from a supposed "Mount Sapo" where ancient Romans sacrificed animals. Rain would send a mix of animal tallow and wood ash down the mountain and into the clay soil on the banks of the Tiber. Eventually, women noticed that it was easier to clean clothes with this "soap". The location of Mount Sapo is unknown, as is the source of the "ancient Roman legend" to which this tale is typically credited.[1] In fact, the Latin word sapo simply means "soap"; it was borrowed from a Celtic or Germanic language, and is cognate with Latin sebum, "tallow", which appears in Pliny the Elder's account. Roman animal sacrifices usually burned only the bones and inedible entrails of the sacrificed animals; edible meat and fat from the sacrifices were taken by the humans rather than the gods. Animal sacrifices in the ancient world would not have included enough fat to make much soap. The legend about Mount Sapo is probably apocryphal.

Arab History
The Arabs made soap from vegetable oil such as olive oil and some aromatic oils such as thyme oil. Lye (Al-Soda Al-Kawia) was used for the first time, and the formula hasn't changed from the current soap sold in the market. From the beginning of the 7th century, soap was produced in Nablus (West Bank,Palestine), Kufa (Iraq) and Basra (Iraq). Soaps, as we know them today, are descendants of historical Arabian Soaps. Arabian Soap was perfumed and colored, some of the soaps were liquid and others were hard. They also had special soap for shaving. It was commercially sold for 3 Dirhams (0.3 Dinars) a piece in 981 AD. Al-Razi ’s manuscript contains recipes for soap. A recently discovered manuscript from the 13th century details more recipes for soap making; e.g. take some sesame oil, a sprinkle of potash, alkali and some lime, mix them all together and boil. When cooked, they are poured into molds and left to set, leaving hard soap.
Historically, soap was made by mixing animal fats with lye. Because of the caustic lye, this was a dangerous procedure (perhaps more dangerous than any present-day home activities) which could result in serious chemical burns or even blindness. Before commercially-produced lye (sodium hydroxide) was commonplace, potash, potassium hydroxide, was produced at home for soap making from the ashes of a hardwood fire.
Castile soap was produced in Europe as early as the 16th century.

Modern History

1922 magazine advertisement for Palmolive Soap
In modern times, the use of soap has become universal in industrialized nations due to a better understanding of the role of hygiene in reducing the population size of pathogenic microorganisms. Manufactured bar soaps first became available in the late nineteenth century, and advertising campaigns in Europe and the United States helped to increase popular awareness of the relationship between cleanliness and health. By the 1950s, soap had gained public acceptance as an instrument of personal hygiene.
Rarely, conditions allow for corpses to naturally turn in to a soap-like substance, such as the Soap Lady on exhibit in the Mutter Museum.