Personally, I think it's because it was simple and free entertainment. Given that there wasn't a taboo around death and watching others die, and it actually being encouraged, like how it was in Anciient Rome, I'd say a lot of people would actually at least try out visiting a gladiatorial contest.
The reason and cause of the crusades was a war between Christians and Moslems which centered around the city of Jerusalem and the Holy places of Palestine. The City of Jerusalem held a Holy significance to the Christian religion. Two major effects of the Crusades were that the kings' authority increased and the Europeans learned about new things from the Muslims they encountered. During the Crusades, the kings increased taxes to fund the cause. Many peasants also left their land to fight, and when they died, the land went to the king.
It's party leadership I'm not 100 percent I hope this helpful
Negotiating to settle disputes between countries.
