Final answer:
Western Christians participated in the Crusades for religious and economic reasons.
Step-by-step explanation:
The motives for western Christians participating in the Crusades were primarily religious and economic. Many knights and nobles were motivated by their religious zeal, the chance to win land and titles, as well as the promise of forgiveness for sins. Additionally, some commoners and poor individuals joined the Crusades for economic opportunities, sacrificing their own land and property to gain resources needed to join the movement.