The Lombard League Defeats an Emperor and Wins Self-Rule
Northern Italian communes beat Frederick Barbarossa in battle, then get their independence in writing
Quick facts
- Diet of Roncaglia
- 1158 CE
- Battle of Legnano
- 1176 CE
- Peace of Constance signed
- June 25, 1183 CE
- Emperor
- Frederick I Barbarossa
What happened
By the 12th century, cities across northern Italy including Milan had grown into self-governing communes wealthy enough to defy the Holy Roman Emperor's authority. When Frederick I Barbarossa asserted sweeping imperial taxation and appointment rights over the Lombard cities at the Diet of Roncaglia in 1158, a coalition of communes formed the Lombard League and went to war with him, defeating an imperial army at the Battle of Legnano in 1176. The conflict ended with the Peace of Constance, signed on June 25, 1183, in which Barbarossa and his son Henry VI granted the League cities the right to keep the regalia and other governing powers they had customarily held, to fortify their own territory, and to maintain or renew their league as they saw fit, while pardoning all injuries and damages from the war.
Why it matters
The Peace of Constance formally recognized what the Lombard cities had already won on the battlefield: the right to govern themselves as autonomous communes under only nominal imperial overlordship. This entrenched self-rule let cities such as Milan, Florence, and Bologna develop their own guild-based governments, courts, and militias for the next three centuries, the political foundation on which Renaissance Florence and Milan would later be built.
How we know
The full Latin text of the 1183 Peace of Constance survives and has been translated for modern scholarship, and the Battle of Legnano and its aftermath are documented in medieval chronicles from both the imperial and Lombard sides of the conflict.
Sources
- World History Encyclopedia. Giuseppe Verdi · Reputable sourceworldhistory.org · The domain "worldhistory.org" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
- Fordham University, Internet History Sourcebooks Project. Medieval Sourcebook: Frederick Barbarossa and the Lombard League · Primary source (author-declared)sourcebooks.fordham.edu · Cited as a "primary" source (no stronger domain match). · Link is live and its text matches the event's key terms (Jul 2026)
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