Many many years ago, there was a mountain near Rome called Mount Sapo. In honor of the goddess Athena, the people from neighboring towns would carry goats and sheep to the top of the hill and burn them atop a sacrificial fire. As the animal fat melted and mixed with the alkaline ash, soap formed and was later carried to the stream below by rain. The women in the towns did their laundry in this stream, finding that their clothes got cleaner at Mount Sapo than anywhere else.
Okay, so that’s probably not true, but it’s a good story, isn’t it? For one, Romans didn’t leave the fatty parts behind during burnt offerings; they took that with them to eat. Besides, the story doesn’t show up anywhere in mythology and no one can remember a Mount Sapo ever existing in the city of seven hills.
The real etymology of soap is still pretty fascinating if language is your cup of tea. The English word “soap” comes from Old English “sape” which comes from West Germanic “*siapo” (meaning dripping thing or resin) which comes from the Proto-Indo-European root “*seib” (meaning to pour out, drip, or trickle). These roots – all the way back to the Proto-Indo-Europeans – refer to soap’s creation using fats and oils.
The (pre-)history of soap makes it all the more bizarre that Europe was plagued with unclean habits for most of the last two centuries. Soap making guilds didn’t arise until the 7th century in Naples. Around the same time, chemists in the Arab world were making soaps with vegetable oils. Soap making really took off in France and Italy in 1200, but it wasn’t until 1600 that vegetable oil soaps started showing up on the continent.