When Wolfgang visited Augsburg in 1777, he gathered many particulars of his father's youth which refreshed the recollections of Leopold himself. We find him writing to his son (October 10, 1777) how, as a boy, he had sung a cantata at the monastery of St. Ulrich, for the wedding of the Hofrath Oefele, and how he had often climbed the broken steps to the organ loft, to sing treble at the Feast of the Holy Cross (November 29, 1777). He afterwards became an excellent organist: a certain Herr von Freisinger, of Munich, told Wolfgang (October 10, 1777) that he knew his father well, he had studied with him, and "had the liveliest recollections of Wessobrunn where my father (this was news to me) played the organ remarkably well. He said: 'It was wonderful, to see his hands and feet going together, but exceedingly fine—yes, he was an extraordinary man. My father thought very highly of him. And how he used to jeer at the priests, when they wanted him to turn monk.'" This last must have been of peculiar interest to Wolfgang, who knew his father only as a devout and strict observer of the Catholic religion. But Leopold remembered the days of his youth, and wrote to his wife (December 15, 1777): "Let me ask, if Wolfgang has not of late neglected to go to confession? God should ever be first in our thoughts! to Him alone must we look for earthly happiness, and we should ever keep eternity in view; young people, I know, are averse to hearing of these things; I was young myself once; but God be thanked, I always came to myself after my youthful follies, fled from all dangers to my soul, and kept steadily in view God, and my honour, and the dangerous consequences of indulgence in sin."
Long-continued exertions and self-denial laid the foundation of Leopold Mozart's character in a conscientious earnestness and devotion to duty in great things as in small; they had the effect also of rendering his judgment of others somewhat hard and uncompromising. This is observable in his relations as an official, and as a teacher, and in his dealings on matters of religion. He was a strict Catholic, and feared nothing so much for his children as the influence which a prolonged stay in Protestant countries might exert on their faith; he remarked with surprise that his travelling companions, Baron Hopfgarten and Baron Bose, had often edified him with their discourse, although they were Lutherans (Paris, April 1, 1764).