The French Revolution involved a massive attack on the Catholic Church. Churches were seized, Masses were made illegal, the very calendar was changed, in an attempt to stamp out Catholic influence entirely. It was remarkably effective. When the Church was restored by Napoleon in 1801, it was in tatters. It was into this mess that the life of Jean Vianney fell. Vianney himself was fortunate; his family had attended illegal Masses in secret and he had been properly catechized, again in secret. When he became a priest in town of Ars, he found an entire countryside of people who considered themselves Catholic but did not know anything about it. People who had not been to church in several decades. An entire generation who had learned literally nothing about it, having never been to church and rarely even told about it. Vianney, a quiet and retiring man by nature, had to stir himself to activity: fiery sermons, traveling around the parish hearing confessions for sometimes sixteen hours a day, hunting down every single parishioner in the parish in order to discuss the faith with them. He became highly respected by the parish, particularly for his good advice in the confessional, and then by parishioners in the surrounding parish. People came for miles and miles to hear the curé from Ars, and especially to go to confession. Then they went back and told their friends and family, and their friends and family came.
The irony of it all is that St. Jean Vianney hated being parish priest. He wanted to live a life of quiet and calm, and there was no quiet and calm in being the priest of a parish that had to be resewn from shreds. He wanted to be a holy man, and was convinced it was almost impossible for a parish priest to become a saint. He literally tried to run away to a monastery several times; his parishioners in each case found him and brought him back. And people from all over Europe sought him out, until he could almost never get out of the confessional. He always wanted to leave, and never had a chance to do so, until he died, still a parish priest in Ars, on August 4, 1859. He was beatified by Pope Pius X, and canonized by Pope Pius XI.