On January 25 we celebrate the Foundation of the Congregation of the Mission in 1625.
In the early days, while St. Vincent and his confreres were giving themselves to the evangelization of the poor, they clearly saw that the effectiveness of their mission to the people could not be sustained unless they also provided for the formation of the clergy. The Catholic Encyclopedia describes it this way:
The Congregation of the Mission founded by St. Vincent has for its chief object together with the missions devotion to the service of ecclesiastics. In France in his day there were in the cities, a certain number of well-educated and distinguished clergymen, but the great majority especially in the country places had no practical means of formation. Many zealous priests of this period, Condren and Berulle of the Oratory, Bourdoise of St. Nicholas, above all Olier of St. Sulpice were preoccupied with the matter. Vincent used to say, as it is of the utmost importance for a military commander after he has conquered a country to leave behind him garrisons to maintain his conquest, so when apostolic men have led the people to God, or brought them back to Him, it is a vital matter to preserve this conquest, by procuring worthy and zealous priests to labour among them.
Learn more in this presentation.