What did people believe caused the bubonic plague?
The bacteria were carried by fleas that were carried by rats. But what did they believe back then? A buncha stuff. Evil spirits, angry god, etcetera. The song ring around the rosy is purportedly about the symptoms of bubonic plague. Because one of the first symptoms was a rose colored ring-like rash. Ring a ring of roses, pocket full of posies (petals were believed to ward off evil spirits) ashes ashes (they burned the bodies) we all fall down.