The 2nd crusade was launched in 1147, however this crusade was a huge failure dew to poor planning
Under the rule of England,France,and the Holy Roman Empire launched at 3rd crusade very quickly however the three kings began to argue amongst themselves causing two kings to leave...
the leader of the crusade made a deal with the leader of Venice, however the knights couldn't afford to pay the bill, the crusade had to attack the city of Zara even though they were a christian city... the 4th crusade took an even stranger turn when attacking Constantinople
The Europeans gained knowledge about mathematics, medicine, gunpowder, architecture, and astronomy from muslims
Many kings increased their wealth and power as they were able to take over the lands of lords and knights who had died on the crusade
Hostile feelings were created during the crusades which even lasted into the present day