Frederick I, also known as Frederick Barbarossa, was a Holy Roman Emperor who reigned from 1155 to 1190. He is remembered for his efforts to consolidate the empire and strengthen its authority over the German states. Frederick sought to expand his influence in Italy, engaging in several military campaigns to assert control over the region. Frederick I was a key figure in the Crusades, participating in the Third Crusade alongside other notable leaders like Richard the Lionheart. His reign was marked by both military successes and challenges, including conflicts with the Pope and various Italian city-states. Frederick's legacy continues to be significant in European history.