Ah, we humans, we enlightened Europeans, enjoyed an almost war-free 13th century. Peace
was everywhere in Europe. What's the catch you may ask?

"It now moved through Italy, France, and Spain. By 1348, it had jumped to England. Also in that year, it crossed the Alps, and began its sweep through Germany, Austria, and Hungary. (In some places, it moved as fast as two and a half miles a day.) By 1349, it had reached Scandinavia. From there, one front hit the ice walls of Greenland and came to a stop. Another circled back to Russia, north of Caffa. “Having closed the noose,” Kelly writes, “the hangman rested.” In four years, the plague had killed at least a third of the population of Europe: twenty-five million people. In the words of the medievalist Norman Cantor, “Nothing like this has happened before or since in the recorded history of mankind.” Measured against Europe’s population today, the Black Death took the equivalent of almost two billion lives."

The Black Death had entered Europe [from the New Yorker book review]