[1][2] War broke out between the Estensi (guelfs) and the Visconti (ghibellins), and the latter besieged Mirandola in early December 1355,[3] with an army of 1,500 horsemen and many masnadiers,[1] who raided the surrounding territory and San Felice sul Panaro.

[4] In the obvious impossibility of resisting such an enemy force, Francesco II Pico, wishing to maintain the dominion of the Pico family over Mirandola and the court of Quarantoli (reacquired just the previous year, taking it away from the Gonzagas, thanks to the investiture by the Emperor Charles IV, who had arrived in Italy) was forced to surrender and ally himself with the Visconti, whose troops were let into the castle of Mirandola in a friendly manner.

However, as early as 1362, the war between the Viscontis and the Este family broke out again: the Pico family renewed their loyalty to the Viscontis, while Niccolò II d'Este allied himself with the Carraresi of Padua, the Gonzaga of Mantua and Cardinal Egidio Albornoz of the Papal Legate of Romagna with the agreement that if the fortress of Mirandola was conquered, it would be handed over to the Mantuans.

Having defeated Bernabò Visconti, the Pico family had no choice but to ask the podestà and captain of Parma for help and, in the meantime, let the troops of the anti-Visconti league enter their castle.

[clarification needed] This was followed by a drinkable truce and then a new war by Bernabò Visconti (this time allied with the Pio di Carpi).