Nobody really knows who made the first bar of soap, or what people used for cleaning before soap was invented.
There is an ancient Roman legend regarding Mount Sapo, where animals were sacrified over a fire to the gods. The legend has it that rain washed a mixture of the melted animal fat from the se sacrifices and ash from the fire down the mountain. It settled in the clay along the Tiber River, and the women washing their clothing there found this clay lathered and cleansed better than the clay elsewhere.
A soaplike substance was also found in clay cylinders during the excavation of ancient Babylon, and was dated to around 2,800 BC. It showed evidence of basic soapmaking methods and ingredients (fats boiled with wood ash), but there is no explanation of whether the creators made this substance with the idea of creating soap.
Actual, documented evidence of soapmaking for the intent of washing and shaving doesnâ€™t exist until much later - around 1100, when soap was being made for sale and personal use in Europe and soapmakers formed guilds to promote their trade. Italy, Spain and France were major soapmaking hubs, especially due to their proximity to sources of olive oil for use in castille soap.
At first the soap was highly taxed as a luxury item, although cleanliness standards and access to soap improved vastly when the taxes were later removed. In the United States, there are records of the second soap to arrive in Jamestown, VA from England containing soapmakers who set up commercial soapmaking. For many years, though, soapmaking was often a household chore, and soap was largely made with waste fats from households.
Larger scale commercial soapmaking began in earnest in the 18th century in Europe when Nicholas Leblanc patented a process for making soda ash (sodium carbonate) from common salt and Ernest Solvay separately discovered the ammonia process, which also used common salt to make soda ash. The availability of low cost, high quality soda ash for soapmaking brought prices for soap down and quantities and qualities available up and industrial production of soap increased greatly.
Commercial soapmaking remained largely the same until World War I, when there was a shortage of the fats required to produce soap. In response, German chemists invented the first synthetic detergent and began producing it commercially. These first early synthetic detergents were largely used for hand dishwashing and washing of delicate fabrics.
When World War II came along and again hampered the availability of fats and oils, however, chemists sprang into action again. In 1946, the first synthetic detergent to contain surfactants and cleaning boosters came to market. The cleaning boosters were phosphates , and they allowed the synthetic detergents to work much better at cleaning everyday garments , rather than just dishes and delicate fabrics.
By 1953, the sales of detergents in the US had surpassed the sales of soap, and soap was largely relegated to personal cleansing uses. By the 1960s, prewash and stain removers came to market, and in the 1970s, hand soap and fabric softeners were introduced and became popular. In the 1980s, detergents for dishwashers , concentrated laundry powders and cold water detergents became popular.
More recently, automatic dishwasher gels, superconcentrated detergents, and detergent pods have become popular as well. The world of soapmaking is fascinating - who knows what will come next?
Source: The Soap and Detergent Association, Washington DC, 2015.