The Crusades is the series of wars between the two groups but if you're looking for a certain one I can further elaborate.
Answer:
The Europeans reinforced the idea that citizens could have little or no say in the government.
A single-issue party (exclusively focused on abortion).
Answer:
I'm pretty sure flooding along rivers created good farmland.
Explanation:
When rivers flood, they put silt onto soil, making it more fertile. When the flooding stops, it makes amazing farmland.
Hope this helps!