Final answer:
Peasants fought in the crusades for religious fervor, economic incentives, and social mobility, but not due to political pressure from local rulers.
Step-by-step explanation:
Peasants fought in the crusades for religious fervor, economic incentives, and social mobility. They were motivated by their religious beliefs and a desire to reclaim the Holy Land, as well as the promise of economic benefits like land and wealth. Additionally, joining the crusades provided an opportunity for social mobility and a chance to improve their status.
However, political pressure from local rulers was not a reason peasants fought in the crusades. While the nobility and powerful nobles may have been influenced by political pressure, the commoners were primarily driven by religious and economic motivations.