Final answer:
The political cause of the Crusades was Pope Urban II using them to increase his authority.
Step-by-step explanation:
The political cause of the Crusades was Pope Urban II using the Crusades to increase his authority. Pope Urban II called for the First Crusade in 1095 and used the opportunity to consolidate his power and strengthen the influence of the papacy. By promoting the Crusades, the Pope could rally European knights and the masses behind a common cause, which boosted his political standing and control.
Learn more about Pope Urban II's political motive in the Crusades