"It is uncertain as to who was the first to invent soap. The earliest recorded evidence of the production of soap-like materials dates back to around 2800 BC in ancient Babylon. A formula for making soap was written on a Sumerian clay tablet around 2500 BC; the soap was produced by heating a mixture of oil and wood ash, the earliest recorded chemical reaction, and used for washing woolen clothing."
(I didn't think Celts couldn't invent anything - chainmail comes to mind - but I do think soap didn't wait for any currently-known people to be invented.)
Re: Cabala
"It is uncertain as to who was the first to invent soap. The earliest recorded evidence of the production of soap-like materials dates back to around 2800 BC in ancient Babylon. A formula for making soap was written on a Sumerian clay tablet around 2500 BC; the soap was produced by heating a mixture of oil and wood ash, the earliest recorded chemical reaction, and used for washing woolen clothing."
(I didn't think Celts couldn't invent anything - chainmail comes to mind - but I do think soap didn't wait for any currently-known people to be invented.)