Answer:
Pope Urban II called for people to recover Jerusalem from the Muslims. - 1st crusade.
Crusaders sacked Constantinople. - 4th crusade.
The Holy Roman Emperor wanted to regain control of the Byzantine Empire. - 1st crusade.
Crusaders massacred Jews in the Rhineland. - 1st crusade.
Crusaders recaptured Jerusalem but killed Jews, Muslims, and Christians in the process. - 1st crusade.
Pope Innocent III hoped to return to Jerusalem to free the city from the Muslims. - 4th crusade.