Castile soap - Wikipedia
History. The origins of Castile soap go back to the Levant, where Aleppo soap-makers have made hard soaps based on olive and laurel oil for millennia.. It is commonly believed that the Crusaders brought Aleppo soap back to Europe in the 11th century, based on the claim that the earliest soap made in Europe was just after the Crusades, but in fact the Greeks knew about soap …