How did soap come to be used so extensively for thousands of years despite germ theory being relatively new?

by Knotix

I understand it's a surfactant and helps physically clean things, but surely there were alternatives with a much more straightforward production process. Soap seems like such an oddly specific substance, yet it appears many civilizations independently settled on its wide use. Furthermore, the fact that it also has fantastic antimicrobial properties must count as one of the most serendipitous coincidences for public health.

DanKensington

Because you don't need germ theory to understand hygiene and general cleanliness. Some reading I dug up for you: