Why were the crusades necessary?

The Crusades were deemed necessary by their proponents for several reasons, primarily to reclaim Jerusalem and other sacred Christian sites from Muslim control. They were also motivated by a desire to unite Christendom against a common enemy, as well as to respond to calls for help from the Byzantine Empire, which faced threats from Islamic forces. Additionally, the Crusades provided an opportunity for European nobles to gain land and wealth, while also addressing growing tensions and violence among the Christian population in Europe itself.