Frederick I of Germany, 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, leading to conflicts with the Papal States and various city-states. Frederick was known for his charismatic leadership and military prowess. He participated in the Third Crusade alongside other European monarchs, including Richard the Lionheart of England. His reign marked a significant period in medieval European history, influencing the political landscape of the time.