The Black Death?!?!

They hopped on rats that were carried on ships that lead to Europe and they are....Fleas!! Fleas carried illness that couldn't be cured at the time because they had no real cures back then. So then if you got The Black Death you wouldn't survive. I think that this would be so scary if I lived in Europe I would get the heck out of there for sure! However eventually they made a cure for it! What helped cure The Black Death?