For about two centuries Italy was divided. There were two main camps, that of the Ghibellines who supported the Holy Roman Empire of the German Nation and that of the Guelphs who supported the pope.
The city of Modena belonged to the friend-imperial camp, while the city of Bologna belonged to the friend-popist side. The beginning of the conflict is placed in 1176 AD. when Emperor Frederick Barbarossa clashed with Pope Alexander III.
The two cities clashed for years. In 1296 Bologna conquered the small towns of Bazzano and Savino that belonged to Modena under the blessing of the then pope Boniface 8th .
Since then the two cities have been in a permanent almost warlike state. And Pope John XXII (of Avignon) had asked the faithful to harm in every way the ruler of Modena Passerino Bonacolzi, offering them forgiveness of sins in this life and the next...
In July 1325, soldiers from Bologna invaded the territory of Modena and plundered what they found in front of them while carrying out the "holy" order. In August they did not repeat the same. But in September, Modena responded in the same way.
Soldiers of Modena even managed to enter the center of Bologna by grabbing an oak bucket from the well there. Grabbing the bucket was considered a great insult and the people of Bologna demanded its return...
As the Modena refused the Bologna gathered 32,000 men (2,000 cavalry, 30,000 infantry, most citizens and peasants armed with tools) and marched against the rival city. The lord of Modena moved against the opponents with 2,000 cavalry and 5,000 foot soldiers in all.
The rivals met in the area of Zapolino on November 15, 1325. The Modena, though outnumbered, easily put the opposing mob to flight. The losses of both armies were, in total, 2,000 dead.
The victors chased the vanquished to the walls of Bologna, seizing another bucket as a… trophy, while destroying six enemy castles and capturing 26 nobles of Bologna.
In January 1326 a peace treaty was signed according to which Bologna returned to Modena all the territories it had conquered since 1296. The bucket in question is kept in Modena to this day.
As for the factions of the Ghibellines and the Guelphs, they continued to fight until the middle phase of the Italian Wars, the first thirty years of the 16th century.
The controversial... bucket.