The Vatican began to review Vincent’s cause in earnest in 1709, with a review of documents pertaining Vincents life and faith, and in 1713 the cause was declared valid and could proceed.

The Vatican, as it does for every cause of sainthood, appointed a canon lawyer to argue against the canonization of an individual. This is the Devil’s Advocate, and for Vincent’s cause was Prospero Lambertini (later Pope Benedict XIV). He argued Vincent’s unworthiness by pointing out everything from Vincent’s friendship with a heretical Jansenist abbot, to Vincent’s having abandoned several of his parish appointments, to his knowledge of mixing medicines (considered alchemy, and thus diabolical). Despite these objections, the beatification process advanced. Vincent was beatified on August 21, 1729, at St. Peter’s in Rome.

Miracles are a very important part of the canonization process. Many supposed miracles attributed to Vincent’s intercession were scrutinized by the Vatican, with two eventually chosen as valid: a nun cured of ulcers, and a laywoman cured of paralysis. Though the Devil’s Advocate argued against the first, stating the nun in question was too learned for a woman, he lost his case. With the approval of these two miracles, the canonization process was complete; Vincent would become a saint of the Catholic Church.

On June 16, 1737, at a mass officiated by Pope Clement XII at St. John Lateran in Rome, Vincent was officially canonized. Fr. Luigi Mezzadri, C.M. writes about that day in his history of the Vincentians:

The procession, which began at six [a.m.], lasted more than three hours due to the enormous gathering of people. Twenty-six cardinals, bishops, patriarchs, and other clergy participated During the ceremony, the pope was presented with two decorated and painted candles weighing sixty pounds each two turtledoves, two golden loaves, two pigeons, and two barrels of wine, all donated by noblemen, cardinals, and friends of the Congregation.*

from the article “Happy Feast Day of St. Vincent de Paul: The Story of His Canonization” by Andrew Rea / September 27, 2013 / Posted in the Special Collections and Archives of the Depaul University Library. Our thanks to Andrew for the informative post!