The Black Death reached its pinnacle in the early 1350s and then began to decline, though it did not truly end, explains The History Channel. Scholars still debate the reason for the decline of the Black Death, though many agree it was likely a combination of several factors.
It is widely believed the Black Death initially spread through rats on trade ships. Perhaps via coincidence, the Black Death began to wane when trading slowed after many people became paranoid about interacting with others and traveling away from home. The spread of the Black Death also slowed as hygiene and living conditions improved. The disease was spread through fleas and rats, both of which were attracted by poor hygiene and unclean conditions. Scholars also postulate that the Black Death simply ran its course. They state the disease never actually completely disappeared, but continued to reoccur in pockets through the 17th century, when significant medical advances made it possible to better understand the biology of the disease. Since colder nations, such as those in Scandinavia, were not as severely affected as other parts of Europe, it is also possible that weather patterns played a role in the decline of the Black Death.