The paper below demonstrates that the science of economics did not begin with Adam Smith. Scholastic thought, despite its relative indifference to the subject, made a significant contribution to economic theory when it took on matters such as price behavior and the problems of a monopoly. The author says that in writing The Wealth of Nations, Smith based himself both on the writings of physiocrats and mercantilists as well as on ideas and concepts dispersed throughout philosophy, legal and history books. The origin of his theory of monopoly, according to de Roover, can be traced back to Aristotle and is linked to the great thinkers of all times. With great care, arguments are gathered that are contrary to monopolistic practices wielded by scholastic and post-scholastic authors, demonstrating that although Thomas of Aquinas did not expound on these subjects, his disciples and followers made significant contributions to the development of economics as a science.