The probability calculus is rooted in games of chance, and arose in the mid 1600s in response to a question raised by an inveterate gambler, or at least so the story goes. In this talk, Christian Genest will give an overview of the real motivations, major contributions and significant interactions between some of the key players in the development of this theory in the sesquicentennial period before the publication of Laplace’s Analytic Theory of Probability in 1812.