This was a series of military expeditions to reclaim the "Holy Land".
What are the Crusades?
Our attacks on Western Europe led to peasants being scared and agreeing to work the land for protection. Leading to the rise of feudalism.
Who are the Vikings?
This is what the manuscripts of the monks did for the world.
Preserved the knowledge of western civilization
This is how the Hundred Years' War contributed to the decline of feudalism?
What is Longbow and cannon fire doing the work of hundreds of knights, meaning knights were no longer needed as much?
This geographic feature played a key role in agricultural development in Europe, allowing them to farm despite how close Europe is to the Arctic Circle.
What is the North Atlantic Drift?