Why had the Papal States nearly dissolved by the 15th century?

By the 15th century, the Papal States had faced near dissolution primarily due to the loss of effective papal authority during the Avignon papacy (1309–1377), when the papal residence moved from Rome to France. During this period, papal control over Italian territories became increasingly tenuous as local powers, such as the Visconti of Milan and the city of Florence, challenged the church's influence.1

The situation was further destabilized by the Great Schism (1378–1417), a period of internal crisis where rival popes ruled from different locations, severely undermining the papacy's political and administrative integrity. While military leaders like Gil Cardinal Álvarez Carrillo de Albornoz attempted to reconquer the territories in the mid-14th century, these gains were fragile. It was not until the election of Martin V in 1417, which ended the schism, that the papacy began the long process of reestablishing control over central Italy.123