Frederick II caught the Lombard League’s army in retreat at Cortenuova on 27 November 1237 and destroyed it, taking the Milanese carroccio and parading it in triumph at Cremona.
Cortenuova, fought on 27 November 1237 on the Oglio, was the most complete victory Frederick II ever won in Italy and the clearest demonstration that winning battles was not how the Lombard question would be settled. He tricked the League army into believing the campaigning season was over, caught its column strung out on the march, and broke it. Thousands were killed or drowned in the flooded rivers, several thousand were captured, and the carroccio of Milan — the ox-drawn war-wagon that carried the commune’s banner and altar — fell into his hands.
He then did something more interesting than the battle. He staged a Roman triumph at Cremona, with the carroccio drawn by an elephant and the captured podestà of Milan tied to its mast, and afterwards sent the wagon to Rome as a gift to the Roman commune, to be displayed on the Capitol. It was a statement about what kind of emperor he claimed to be. Within a year the campaign had stalled before the walls of Brescia, and within two he was excommunicated and fighting for his position across the whole of Italy.
The northern Italian communes had beaten Frederick Barbarossa at Legnano in 1176 and won the settlement at Constance in 1183 that let them govern themselves while acknowledging imperial overlordship. His grandson meant to reverse the substance of that. Frederick II came north with a programme of restoring imperial rights — taxation, the appointment of officials, the regalian claims — and in 1226 the cities re-formed their alliance, Milan at its head with Bologna, Brescia, Piacenza and their neighbours, and closed the Alpine passes against the imperial diet summoned to Cremona.
The quarrel was sharpened by the papacy, which regarded an emperor who ruled Sicily in the south and Germany in the north as a strategic threat to the papal lands between them. Gregory IX excommunicated Frederick in 1227 over a delayed crusade and again backed the communes as his leverage. By 1237 Frederick had settled Germany, brought his son Enzo and an army of German knights into Italy, and was campaigning to force the League to accept unconditional imperial authority.
The League army had come out to shadow the imperial force and block its march west toward Milan, and the two armies manoeuvred through the autumn without either being able to force a decision. In late November Frederick announced that he was ending the campaign and moving into winter quarters at Cremona, and began marching in that direction. It was plausible — the season was over, the rains had come — and the League believed it, broke up its concentration and started its own contingents home.
He turned the column round and came back fast. On 27 November the imperial army caught the Milanese and their allies strung out on the road near Cortenuova, in country cut by the Oglio and the Serio and soaked by autumn rain. The intelligence that made this possible came from Ezzelino III da Romano and from Frederick’s allies among the cities that hated Milan — Cremona above all, which had been Milan’s rival for a century.
The Milanese did what communal armies did when caught: they halted around the carroccio and made a stand. The wagon was not a piece of equipment but the commune’s honour on wheels, carrying its banner and a mass altar, and abandoning it was unthinkable, which is precisely why it worked as an anchor for a rearguard. German knights and the Saracen archers from Lucera came in against it, and the fighting around the wagon went on until dark, with the Milanese giving ground slowly and holding.
The army broke in the night rather than in the battle. Once darkness stopped the fighting, contingents began slipping away toward home; the retreat lost its shape, and the rivers that had been the position’s protection became its killer, with men drowning in the flooded Oglio and Serio in the dark. In the morning the imperial troops took the abandoned carroccio and its escort. Perhaps three to four thousand were dead, and four to five thousand were prisoners, among them Pietro Tiepolo.
On 1 December Frederick entered Cremona in a procession consciously modelled on a Roman triumph: the captured carroccio drawn through the streets by an elephant from his menagerie, with Pietro Tiepolo bound to the mast where the banner should have flown. The theatre was the point. Frederick’s whole claim was that he was the Roman emperor restored, not merely a German king with Italian ambitions, and a triumph was the most legible way of saying so to an Italian audience.
He then sent the carroccio to Rome, as a gift to the Senate and people, where it was set up on the Capitol with an inscription recording that Caesar had sent it. This was aimed at Gregory IX: an emperor honouring the Roman commune over the head of the pope who claimed the city. Tiepolo, whose father was the Doge of Venice, was kept as a hostage against Venetian policy and eventually hanged at Trani in 1249. The elephant, the inscription and the hostage all belong to the same argument about who the emperor was.
Frederick made the mistake of treating a battlefield result as a political surrender. When Milan opened negotiations he demanded unconditional submission, which no commune could grant and survive as a commune; the city refused, and the war that might have ended in the winter of 1237 went on. As one modern assessment puts it, Milan could lose thousands of men, its podestà and its carroccio without losing its walls, its government, its money or its ability to raise another army next year.
The next season showed what that meant. The siege of Brescia through the summer and autumn of 1238 failed outright, and the spell of invincibility broke with it. Gregory IX excommunicated Frederick again in March 1239 and the conflict widened into a war for Italy: the deposition pronounced at the Council of Lyon in 1245, the loss of his siege-city Vittoria to a sortie from Parma in 1248, the capture of his son Enzo at Fossalta in 1249. Frederick died in December 1250 with the Lombard question exactly where Cortenuova had failed to settle it, and the Hohenstaufen cause in Italy did not outlive his sons.