Answer: Vikings, Muslims, and Magyars invaded Europe at a time of political weakness.
Explanation:
Feudalism refers to a system where the King or Queen was the absolute monarch and as a result owned all the land but could give it to Nobles who would then become rich and powerful.
This system was as a result of people needing such protection that they bounded around the Nobles to protect them when invasions from groups such as the Vikings, the Muslims and the Magyars threatened their security in a way the monarchs could not effectively protect them.
