How did the problem in isreal start.

The history of the Israeli–Palestinian conflict began with the establishment of the state of Israel in 1948. This conflict came from the intercommunal violence in Mandatory Palestine between Israelis and Arabs from 1920 and erupted into full-scale hostilities in the 1947–48 civil war.

although the crusades failed to capture jerusalem, they had several major impacts on western europe. they increased the authority of the king: sometimes nobles died in battle without leaving an heir in which case the king got their land. kings passed taxes to pay for the crusades.