This paper intends to study the influence of the Benjamin Constant Reform in the Mathematics curriculum of the Pedro II School. Benjamin Constant was a Mathematics teacher and the Head of the Instruction, Mail and Telegraph Ministry (1890-1). He intended to reform all levels of Brazilian education and decreed the Reform named after him. The Reform had an encyclopedic nature, inflating the content of the programs for each subject, especially the one for Mathematics. The Pedro II School was founded in 1837-8 to serve as a model for Brazilian secondary education, which was characterized as targeted to the social/economical elite; however, the School does not seem to have fulfilled the initial expectations. The Reform altered the Mathematics syllabus of the Pedro II School; among other changes, it added, from 1895 on, notions of differential and integral calculus. To analyze the influence of the Reform in the aforementioned syllabi, this paper compares the Mathematics curriculum in use in 1880-1890 to the ones used later on (1890-1900). The theoretical and methodological bases for this research were Ivor Goodson and Jean-François Sirinelli. The paper also aims to establish Benjamin Constant as an intellectual, and to examine if and how this status would have affected the Reform. The research uses several documents: normative acts (such as the decrees that established educational reforms in Brazil, during the Empire and in the early Republic), curriculum documents (Mathematics syllabi of the Pedro II School in the 1880-1900 period) and documents produced by B. Constant himself.