The Peace of Constance was a privilege granted by Frederick I, Holy Roman Emperor, and his son and co-ruler, Henry VI, King of the Romans, to the members of the Lombard League to end the state of rebellion (war) that had been ongoing since 1167. It was a permanent peace that superseded the six-year truce imposed by the Treaty of Venice.

Frederick Barbarossa, also known as Frederick I, was the Holy Roman Emperor from 1155 until his death 35 years later in 1190. He was elected King of Germany in Frankfurt on 4 March 1152 and crowned in Aachen on 9 March 1152. He was crowned King of Italy on 24 April 1155 in Pavia and emperor by Pope Adrian IV on 18 June 1155 in Rome. Two years later, the term sacrum ("holy") first appeared in a document in connection with his empire. He was later formally crowned King of Burgundy, at Arles on 30 June 1178. He was named Barbarossa by the northern Italian cities which he attempted to rule: Barbarossa means "red beard" in Italian; in German, he was known as Kaiser Rotbart, which in English means "Emperor Redbeard." The prevalence of the Italian nickname, even in later German usage, reflects the centrality of the Italian campaigns to his career.