Final answer:
The Frankish Carolingian Empire needed the support of the church and the pope to validate their expansion across Europe.
Step-by-step explanation:
The Frankish Carolingian Empire needed the support of the church and the pope to validate their expansion across Europe.
By forming an alliance with the popes, the Carolingian rulers gained legitimacy and independence from the Byzantine Empire, which allowed them to conquer new territories and revive the idea of empire. The support of the church and the pope also helped the Carolingians maintain control over the church in conflicts with kings and emperors.
Overall, the support of the church and the pope was crucial in ensuring the success and validation of the Frankish Carolingian Empire's expansion across Europe.