Thinking how ancient Rome there was an importance of hygiene to a degree but in the Middle Ages and even after it seems to be a hygiene less waste land in many part or Europe. Or was it that the dominant cultures prevailed in their stinky ways over time?
I'm afraid your question rests on a false premise; the importance of hygiene didn't drop in Europe after the Romans went. The following previous answers are most instructive on this matter, and any and all further input is most welcome.