After Emperor Lothair III died in late 1137, leading princes chose Conrad III of the Hohenstaufen family as king (often called “King of the Romans”). His election opened a long rivalry with the Welf faction and set the political base for later Hohenstaufen interventions in Italy.
Conrad III left Germany to take part in the Second Crusade, weakening his ability to enforce royal authority at home. The campaign also introduced his nephew Frederick (the future Barbarossa) to large-scale international politics and military logistics.
After Conrad III died, the princes elected Frederick I (“Barbarossa”) as king. His election mattered because he aimed to strengthen imperial authority, especially in northern and central Italy where wealthy cities often governed themselves.
Frederick’s imperial coronation by the pope gave him the traditional prestige needed to press claims in Italy. It also sharpened questions that would dominate his reign: how much power the emperor could exercise over Italian cities and over the church’s political role.
At Roncaglia, Frederick and his supporters publicly listed the crown’s legal rights (such as tolls, coinage, and courts) in northern Italy. This was a turning point because it framed the conflict with Italian communes as a legal struggle over who had the right to govern and tax.
Frederick’s army took Milan and ordered major destruction soon after. The harsh outcome pushed other cities to cooperate against him, helping drive the formation of broader anti-imperial alliances in northern Italy.
The Lombard League’s victory at Legnano showed that the emperor could be beaten by coordinated city forces. After this defeat, Frederick shifted from repeated campaigns to negotiated settlements, changing the direction of imperial policy in Italy.
At Venice, Frederick made peace with Pope Alexander III and his allies, ending a major church–empire conflict and establishing a multi-year truce with the Lombard League. This agreement created the political space for a more permanent settlement on city rights.
The Peace of Constance formalized a compromise: the Lombard communes kept important local powers while accepting the emperor’s overlordship. It marked a key limit on direct imperial control in northern Italy, shaping later Hohenstaufen strategy there.
Henry VI, Frederick I’s son, became emperor and pursued a more expansive Italian policy. His rule mattered because it linked imperial ambitions to southern Italy through his marriage and claims to Sicily, increasing papal fears of being surrounded.
Henry’s takeover of Sicily created a powerful north–south combination: the empire’s German lands and the wealthy Sicilian kingdom under one ruler. This “encirclement” of the Papal States heightened long-term conflict between the Hohenstaufen and the papacy.
Frederick II’s coronation confirmed the Hohenstaufen hold on the imperial title while he also ruled Sicily. His dual power base made him unusually strong in Italy, but also set him on a collision course with popes who opposed a dominant emperor in the peninsula.
Pope Gregory IX excommunicated Frederick after delays in fulfilling a crusade commitment. The break mattered in Italy because it turned disputes over authority into open war and propaganda, with papal supporters and imperial supporters mobilizing across the peninsula.
Frederick and Gregory IX negotiated peace after fighting linked to the excommunication. The treaty temporarily restored cooperation, but it did not solve deeper disputes about imperial power in Italy—especially relations with the Lombard cities.
Frederick promulgated the Liber Augustalis (Constitutions of Melfi) as a wide-ranging law code for the Kingdom of Sicily. It strengthened royal courts and administration, giving Frederick a more organized southern base for renewed campaigns and diplomacy in Italy.
Frederick defeated the Second Lombard League at Cortenuova, capturing many prisoners and symbolic city standards. The victory briefly strengthened imperial leverage in northern Italy, but it also intensified resistance and papal alarm about his growing power.
At the First Council of Lyon, Pope Innocent IV formally pronounced Frederick deposed, escalating the struggle into a Europe-wide political crisis. In practice, Frederick continued fighting, but the decision encouraged rivals and weakened the dynasty’s long-term position.
Frederick died in southern Italy, leaving his son Conrad IV to defend Hohenstaufen claims in Germany and Italy. His death is often treated as the beginning of a rapid decline: without his personal authority, resistance to Hohenstaufen rule grew and the empire moved toward a broader interregnum-like instability.
Conrad IV’s death removed the last adult Hohenstaufen leader able to coordinate a serious recovery in Italy. The result was a clearer collapse of Hohenstaufen power in the peninsula, with later struggles carried on by weaker heirs and allies rather than an emperor who could command both Germany and Italy.
Hohenstaufen Emperors and the Italian Campaigns (1138–1254)