The causes of the war were rooted in interrelated issues, Florentine opposition to the expansion of the Papal States in central Italy , and antipathy toward the Parte Guelfa in Florence. Specifically, Florence feared in the autumn of 1372 that Gregory XI intended to reoccupy a strip of territory near Lunigiana, which Florence had conquered from Bernabò Visconti, and that the Ubaldini might switch from Florentine to Papal allegiance. Gregory XI also harbored various grievances against Florence for their refusal to aid him directly in his war against the Visconti of Milan. When Gregory XI's war against Milan ended in 1375, many Florentines feared that the pope would turn his military attention toward Tuscany; thus, Florence paid off Gregory XI's main military commander, English condottiere John Hawkwood, with 130,000 florins, extracted from local clergy, bishops, abbots, monasteries, and ecclesiastical institutions, by an eight-member committee appointed by the Signoria of Florence, the Otto dei Preti. Hawkwood also received a 600 florin annual salary for the next five years and a lifetime annual pension of 1,200 florins. The transalpine mercenaries employed by Gregory XI against Milan, now unemployed, were often a source of friction and conflict in papal towns.. Which happened first, the end of war against Milan or Florence paying off Gregory XI's main military commander?