Vincent de Paul's portrait was first painted as he was coming towards the end of his life. The initial portrait,  by Simon Françoys, was not actually completed till after Vincent's death in 1660.  Vincent was unwilling to have his portrait painted,  so it was done without his knowledge by the artist seating himself unobtrusively in the chapel or dining room at St Lazare (Paris), making his sketches while Vincent was otherwise occupied, and later on committing the sketches to canvas.  The famous Brother Robineau CM,  secretary and scribe for Vincent,  was in the thick of this 'conspiracy'.  (Alas for 'Vincentian simplicity'!)  So the portraits we see of Vincent usually depict a man in old age.  Details of the subterfuge can be found in  Pierre Coste's The Life and Works of Vincent de Paul, Vol III,  Ch LXIV, p.377 , New City Press, New York, 1987 (Translation by Joseph Leonard CM). The above portrait, painted by  Marjorie Prophet of  Windsor NSW in 1991, and presented to Fr Gerald Scott CM,  represents Vincent as a younger priest.  The artist   based the painting on a number of portraits and engravings of Vincent at a later age.  The energy and life in the face and eyes of Vincent are characteristic of what we know about him. The painting is currently at the Vincentian Community House at Marsfield (Sydney).