soap making history

Soap making was widespread in settled communities, where cleaning was given a higher priority than that accorded it by hunter-gatherers. Soft soap, also known as black soap is mentioned frequently in British Medieval medical texts. At first, it was made with hemp oil and then much later, linseed oil.

http://www.permaculture.co.uk/articles/short-history-soap-pre-petroleum-age-how-make-your-own-biodegradable-plant-soaps