The end of the Avignon papacy
For well over 67 years, the pope, his court and the administration of the Church had been residing in Avignon, a large town commanding an important crossing on the Rhone River in southern France. They had come to live there for many historical, political, and personal reasons .
One reason was the extended quarrel between Pope Boniface VIII and King Philip the Fair of France, which had ended in 1303 with the Pope being captured and placed on trial. To Clement V, elected a year later in Lyons after a difficult conclave that lasted 11 months, it seemed prudent to remain near King Philip, to dissuade him from resuming the trial against the dead Pope Boniface.
Another reason was the civil war which was devastating Italy, and rendering Rome unruly and totally insecure. Avignon, on the other hand, belonged to vassals of the Pope; it was quite safe, and, while providing easy communication with France and Italy, its relative tranquillity could allow the papacy to govern the church independently .
Pope Clement V, a Frenchman who was politically a subject of King Edward I of England, had intended to go to Rome as soon as the questions between the French king and the papacy were solved, but his health deteriorated because of cancer, and neither he nor his five successors were able to return to Rome -- mainly because of the war in Italy. Meanwhile, the papal court became almost entirely French and the Papal States were governed by French legates.
In 1376 the Pope was Gregory XI, a studious, devout, and timid man, who had been elected to the papacy in 1370 at the age of 40 although he was still only a deacon. He soon found himself at war with the Duke of Milan, who had invaded the Papal States in Italy because, among other reasons, many Italians were determined no longer to remain under the rule of French legates. The Republic of Florence had sided with Milan, as had Perugia, Bologna, and many other regions. Soon the whole of Italy was once again in arms. The Pope replied by placing Florence under an interdict and despatching a large army of mercenaries to subdue it.
It was then that the Florentines called on St. Catherine of Siena.
Catherine Benincasa was a young (29) Dominican tertiary who had won a unique place in the estimation of her fellow citizens of Siena, and whose reputation for holiness and miracles had spread to most of northern Italy. Well-known for her mystical visions and consolations, she had devoted herself since the age of 19 to nursing and to visiting in prison those condemned to execution. So great was the effect of her work that three Dominicans had been especially charged full time to hear the confessions of those whom she induced to amend their lives.
Gradually there had gathered around her a hand of friends and disciples: some members of her family (she was one of 25 children), her confessors, a number of students, artists, a hermit. They called her ''Mamma" and felt bound to her by the tenderest affection. She considered them children given to her by God that she might lead them to perfection . And it was to them that she began to write what became the great series of her "Letters" -- at first missives of spiritual instruction and encouragement, later trenchant comments and insightful opinions on public affairs.
Catherine threw herself energetically into Pope Gregory XI's appeal for another crusade, and later, at the time of the papal interdict against Florence, she offered to mediate the dispute between that city and the Holy See.
Catherine arrived in Avignon on June 18, 1376, and soon had an audience with Pope Gregory. Within a month, using her remarkable combination of outspokenness, familiarity, and deep respect, she succeeded where others had failed for over two generations. On September 13, 1376, the Pope started from Avignon to return to Rome.
Gregory XI's return did not put an immediate end to the Church's political problems. Within two years, at the time of the election of Urban VI, the French cardinals elected a rival pope in Avignon. But Catherine's insistence that the popes return to their natural abode inaugurated the Renaissance papacy which would, in turn, restore the ecclesiastical and temporal power of the Vicar of Christ.