What is Castile Soap?
Early soap-makers in Europe did not have easy access to laurel oil and therefore dropped it from their formulations, thereby creating an olive-oil soap now known as Castile soap
[Source] Wikipedia: https://en.wikipedia.org/wiki/Castile_soap
The soap making process is a complicated dance that strikes to balance cleaning and feel. Different oils are used to bring certain characteristics to the soap; some are good for cleansing power, some are good for lather, others aid in bubble creation and others still are vital in moisturizing and conditioning. No one oil is effective nor able to bring all of these attributes. Olive oil's main strength lies in it's conditioning properties. It is able to adequately clean while still being very mild and gentle on the skin.