Answer:
Charlemagne.
Explanation:
After the fall of the Early Roman Empire in 476 BC, the kingdom of Europe fell into the hands of many small kingdoms. But after about three centuries after that, King Charlemagne began his reign and helped unite a large part of Europe into his kingdom.
King Charlemagne was the king of the Franks who came to the throne in 751 BC. His rule began with the plan to unite all Germanic people under his power. He also made it a point to convert the subjects from the captured places into Christianity, thereby propagating the religion on a large scale. That was one of the reasons why Christianity emerged strongly during the Roman empire.
Thus, the correct answer is King Charlemagne.
