The Justinian plague definitely happened ... Smallpox (15th - 17th centuries) Europeans introduced a number of new diseases when they first arrived in the continents of the Americas in 1492.

a bacterial disease, among the deadliest pandemics and epidemics in the world, also including the Plague of the Justinian in ...

In fact, scientists think that it may have been around before the 1300s, as there are records of a similar disease in Rome in 146AD, known as the Justinian plague. The symptoms of the plague were ...