December 8, 1841, is the date that, in his Memoirs of the Oratory, Don Bosco identifies as the "first beginning of our Oratory, which blessed by the Lord took that increase, which I certainly could not have imagined then."
On this date, in the church of St. Francis of Assisi, Don Bosco meets Bartolomeo Garelli, an unmotivated but resourceful boy, and manages to win his trust by leveraging one of his talents, the ability to whistle. This is the style of the Preventive System, which arouses the young man's interest and enthusiasm, promotes his self-esteem, and focuses on the value of his person.
And so, with a simple Hail Mary recited together, on that distant December 8, 1841, the Salesian Oratory was started!