Catherine of Siena, a deeply religious woman who had joined the Dominican Third Order at sixteen, has become convinced of the necessity of ending the sixty-eight-year absence of the popes from Rome and had begun to write letters to men and women in authority, especially begging for peace between the republics and principalities of Italy and for the return of the papacy from Avignon to Rome.

She has carried on a long correspondence with Pope Gregory XI, also asking him to reform the clergy and the administration of the Papal States.

Already known for her unusual mystical revelations and the holiness of her life, she travels to Avignon as an ambassador of Florence to present her case personally for ending the war and to persuade Gregory to leave France for Rome, the rightful capital of the papacy (which he will do the following January).