Why did the Black Death happen?

this is complicated but i think this the right; It was an epidemic, or a series of epidemics, of Bubonic Plague that lasted for several decades in the 14th century and wiped out between one third and one half of the population of Europe. The plague was spread by the bites of fleas that were carried on rats.

Unsanitary living conditions contributed to its spread. People of that time did not know how the disease was spread or how to protect themselves from it.

Another reason the Black Death happened is because of the increased demand for trade between the Mediterranean. The increase in trade brought about an increase in ships traveling around the African continent which increased the inscription of sailors which increased the incidents of sailors abandoning their ships.

Along with the movement of products which carried the rats that carried the fleas, the sailors would get sick and abandon their ships or the captain would throw them overboard and then they would spread the decease.

Also the symptoms were red lesions surrounded by white bumps. Which created the kids song. "Ring around the rosie" Referring to the white ring around the red lesions "Pocket full of Posies" People thought that carrying herbs and/or flowers would help ward off the disease But that was not of any help; "Ashes, ashes" Ashes to ashes "We all fall down" Dead

i copied and pasted this btwIf you check snopes.com, you will find that there can be no connection between the Black Death and this childrens' song.