From 1309 to 1377, the popes resided in Avignon, and many of their dominions in Central Italy fell into the hands of local lords. In 1353, Pope Innocent VI sent Gil Álvarez Carrillo de Albornoz, Cardinal of St Clement, into Italy, for the sake of restoring the papal temporal authority. The energetic policies of the Cardinal led to the rapid establishment of a strong and cohesive state that surrounded Florence on all sides and that included cities and territories to which the Florentine republic, in turn, aspired. The full restoration of papal jurisdiction over Perugia (1371), in particular, elicited palpable concern across all Tuscany. In addition, many in Florence feared that the faction connected to the Church (the Guelph party and the Albizzi family) might now be tempted to rely on the Pope's external support to rid itself of its political enemies. Finally, the arrogant style of government of the papal legates who were dispatched from Avignon to the dominions of the State of the Church soon alienated the various peoples who were subject to their rule and created additional tensions with their neighbours: above all, Florence. Despite all this, Florence joined a general anti-Milanese coalition with the Pope in 1372 (and renewed it in 1374), for the sake of checking the expansionist policies of Bernabò and Galeazzo Visconti, lords of Milan, in Northern Italy.

It is against this backdrop that, in the winter of 1374–5, the Legate of Bologna denied Florence permission to buy grain in Romagna, a region under his jurisdiction. In the following summer, a truce being signed with the Visconti (4 June 1375), he dismissed Sir John Hawkwood and his mercenary company, who immediately headed for Tuscany, looking for plunder and ransom. In Florence, many suspected that Hawkwood had passed into Tuscany upon the Legate's encouragement, for it was believed that the latter intended to take revenge on the Tuscan cities that had refused to contribute funding for his war against the Visconti, thus forcing him to suspend it. A plot designed to make Prato – a town under Florentine dominion – fall into Hawkwood's hands was foiled and Florence was forced to pay a huge sum of money to convince the English mercenary to evacuate her territory.