They were Norwegian/Scandinavian people living off the land in cold regions. They were very advanced boatmakers, as their boats could traverse narrow streams and turbulent oceans. In search of riches, they would sail from their homelands to Western Europe (Modern-day UK). Monks, at the time, were peaceful, weaponless, and rich (because they were educated and rich people paid them to teach their kids). This made them the perfect targets for invading Vikings, who easily overpowered them and stole their riches. To keep the Popes/Kings safe from Vikings, Feudalism was invented. People lived in compounds protected by knights. The leader of each compound answered to the king but mostly controlled their own region. This was useful for a while but fell once there were no outside threats.