People used perfumes to ward off the plague in the Middle Ages
The knowledge that germs such as bacteria and viruses are the ones that cause illness is fairly new. Back in the Middle Ages, the plague was thought to be spread through “miasma” or “bad air.” So, it was believed that sweet perfumes, herbs, and burning incense would ward off them from sickness.
Of course, we know that no amount of sweet perfume would keep bacteria or viruses away. However, in an era when there were no plumbing or waste disposal systems, it would not have been a bad idea to carry around something that could keep the smell away.