Soldiers who fought in the Crusades brought back knowledge from the Middle East in areas such as medicine, astronomy, and mathematics. The Pope was also a leading figure in politics during this time, and the Crusades helped to unite the different warring nations of Europe while it was being fought. In addition, many kings and monarchs made their claims to fame or brought themselves to ruin due to their Crusading attempts, the most famous example being Richard the Lionheart.
Blaming the collapse of world trade and other economic failures on Jewish financiers.
If the change in values of one set doesn't affect the values of the other, then the variables are said to have "no correlation" or "zero correlation." A causal relation between two events exists if the occurrence of the first causes the other.
