 Aristotle replaced Cicero and Boethius as supreme authority on probability in the thirteenth century. This is also the time when medieval probability discourse fully unfolded. For the period from (roughly) 1200 to 1500, it is possible to identify four different concepts of probability: the endoxic, proto-frequentist, testimonial or juridical, and semantic. The number of concepts is, however, a matter of interpretation since it is possible to split up the juridical category of probability  further.[12]