Even more than you wanted to know about soap.

Soap was said to have been discovered on Sappo Hill in Rome when a group of women were washing their clothes in the River Tiber at the base of a hill, downstream from which the animal fats from the sacrifices ran down into the river and created soapy clay mixture. They soon discovered that by using these cleansing waters, the clothes were becoming cleaner, much faster.

However, inscriptions on Babylonian clay containers dated at 2800 B.C. may possibly present the earliest known written soap recipe. The product was made from fats combined with wood ash and water. These early references to soap and soap making were intended to wash wool and cotton in preparation for weaving into cloth.  Soap was not yet used to wash the body.

The Ebers papyrus (Egypt, 1550 BC) reveals that ancient Egyptians combined both animal and vegetable oils with alkaline salts to produce a soap-like substance. They used this mixture for treating sores and skin diseases as well as washing.

According to the Pliny the Elder, the Phoenicians made soap from goat's tallow and wood ashes in 600 BC.
The ancient Greeks used a lye and ash mixture as a cleanser for both pots and statues.

Early Romans used urine to make a soap-like substance in the first century A.D. Later, they combined goat's tallow and the ashes of the beech tree to make both hard and soft soap products. The discovery of an entire soap factory lies in the ruins of Pompeii, one of the cities destroyed by the volcanic eruption of Mt. Vesuvius in 79 A.D.

 Soap for personal cleansing became popular during the later centuries of the Roman era.

The Celts, who used animal fats and ashes to make their soap, named it "saipo".

The Arabs produced the soap from vegetable oil as olive oil and also added aromatic oils, like thyme oil. A Sodium Lye NaOH formula was used for the first time.  Arabian soap was both perfumed and colored, and they made both liquid and hard soaps.

Soap-makers in Naples were guild members in the late sixth century, and in the 8th century, soap-making became increasingly well known in both Italy and Spain. The De Villis, (800 B.C), mentions soap as being one of the products that the stewards of royal estates were to tally. Soap-making is mentioned both as "women's work" and as the produce of "good workmen" alongside other necessities such as the produce of carpenters, blacksmiths, and bakers.

Finer soaps were later produced in Europe from the 16th century, using vegetable oils (such as olive or coconut oil) as opposed to animal fats. Many of these soaps are still produced, both industrially and by small-scale artisans. Castile soap is a popular example of one of the oldest "white soaps" of Italy.

Today, the use of soap has become universal, due to a greater understanding of the role of personal hygiene in the reduction of pathogenic microorganisms. Industrially manufactured bar soaps first became available in the late eighteenth century, as advertising campaigns in Europe and the United States promoted popular awareness of the relationship between cleanliness and health.

"Bee My Honey" Goat's Milk Soap - Naked Bear Soapworks