The Battle of Zappolino, the only battle of the War of the Oaken Bucket, was fought in November 1325 between forces representing the Italian towns of Bologna and Modena, an incident in the series of raids and reprisals between the two cities that were part of the larger conflicts of Guelphs and Ghibellines. The Modenese were victorious. Though many clashes between Guelphs and Ghibellines loomed larger to contemporaries than to historians, the unusually-large encounter involved 4,000 estimated cavalry and some 35,000 foot soldiers, and 2,000 men lost their lives. The location of the battle, at the foot of a hill just outside the castle walls, is now a frazione of the municipality of Castello di Serravalle, Emilia-Romagna.
Setting
Their boundaries had been set by Frederick II, Holy Roman Emperor a century earlier, but competitive friction along their mutual marches between Ghibelline Modena, with the Emperor as a patron, and Guelf Bologna, with the Pope as a patron, had flared over decades. In 1296, the Bolognese invaded the Modenese lands of Bazzano and Savigno, with the support of Pope Boniface VIII, who recognized in 1298 Guelf possession of the border castles. Within the two cities, the situation was complicated by numbers of exiles and divided loyalties. In Modena, the struggle for power after the death of Obizzo II d'Este, which divided his sons' friends into hostile camps, was resolved in favor of Azzo VIII, who confronted Bologna partly to bolster his lukewarm reception by his own city's nobles. His elected successor, the Mantuan Passerino Bonacolsi, the agent of Louis of Bavaria, King of the Romans, pursued the embittered war politics, with Parma, Reggio and Modena also under his power. John XXII declared him a rebel against the Church and granted indulgences as befitted a Crusader to any who could harm his person or his possessions.
In the months before the battle, border clashes intensified. In July, the Bolognese entered the Modenese territory and laid waste the fields in the section "between the canals" by fire and sword. In August, a Bolognese rabble led by their podestà, spent two weeks ravaging the lands of Modena. In September, Mantua took its turn, and at the end of that month, the strategic Bolognese rocca of Monteveglio was betrayed to Modena by malcontents. Two renegade castellans were beheaded.
Battle
As the Bolognese chronicler Matteo Griffoni tells it, the militia and the rabble of Bologna headed by their podestà, aided by allies from Florence and Romagna, besieged the fortress of Monteveglio. Quickly, an opposing force arrived, headed by Cangrande della Scala, the leader of the Ghibelline faction, Azzone Visconti of Milan, with many of his professional German troops, and Rinaldo, marchese of Ferrara, leading forces of Modena, Mantua and Ferrara. Cangrande soon departed for Verona, but the Bolognese took for their captain the condottiero Malatesta, lord of Rimini.
The battle took place 15 November 1325 around sunset. The Bolognese had 30,000 foot soldiers, who would have been haphazardly armed, and 2500 horsemen facing 2800 horsemen on the Modenese side, who were supported by 5000 foot soldiers. Bonacolsi devised a plan to feign a river crossing in an effort to distract part of the Bolognese forces. They put this tactic in action a day prior to the main battle at Zappolino. During the cover of night the Modenese headed south to the modern town of Marano sul Panaro. They crossed the river, and after a short skirmish with a Bolognese vanguard began to march towards Zappolino. The Bolognese realizing they had fallen for a trap began to recall the men that had been sent to the north. The Modenese were positioned close to where the town of Ziribega stands today, while the Bolognese were positioned on a slope coming down from the hill that the fortress was located on. Bonacolsi realized that if he did not strike now while the Bolognese were unorganized it would be far more difficult to attain victory. The Modenese began an attack on the Bolognese lines, and soon heavy fighting erupted. Bonacolsi sent his cavalry around the side, in order to attack the Bolognese from behind.