In the wake of Pope Sixtus IV’s excommunication of Lorenzo the Magnificent, an anti-papal front formed in Italy, and even the Tuscan bishops sided with Lorenzo. A letter (the Florentine Synod) was sent to Emperor Frederick III of Habsburg, and to the sovereigns of Spain and France. The conditions were laid for an unavoidable armed conflict that would see papal and Neapolitan troops advance into Tuscan territory. Formal support from Milan for the Este family of Ferrara-Modena arrived only gradually.
