What important victory did one founder of the Carolingians achieve?

He convinced all Europeans to convert to Christianity.
He won the title of first warrior king of France.
He fought to make Spain the most powerful country in Europe.
He defeated a Muslim invasion from Spain

He defeated a Muslim invasion from Spain

Explanation:

By 700, a majordomo was the most powerful person in the Frankish Kingdom .From 719 this position was in the hands Charles Martel, who become the important person in the country .In the battle of Poitiers (near Tours) in 732 he defeated Arabs, and after the battle he was called Charles the Hammer and Christian Hero.

The answer to that would be prussia which would later be germany