The introduction of a new analytical method, thanks fundamentally to François Viète and René Descartes (1596-1650) and the later dissemination of their works, resulted in a profound change in the way of thinking and doing mathematics. This change, known as process of algebrization, occurred during the seventeenth and early eighteenth centuries and allowed a great transformation in mathematics. Among many other consequences, this process gave rise to the treatment of the results with the new analytical method in the classic treatises, which allowed new visions of such treatises and the obtention of new results. Among those treatises is the Arithmetic of Diophantus of Alexandria (approx. 200-284) which was written, using the new algebraic language, by the French mathematician Jacques Ozanam (1640-1718), who in addition to profusely increasing the original problems of Diophant, solved them in a general way, thus obtaining multiple geometric consequences. The work is handwritten, it has never been published, it has been lost for almost 300 years and the known references show its importance. We will show that Ozanam's manuscript was quoted as an important work on several occasions by others mathematicians of the time, among which stands out G. W. Leibniz (1646Leibniz ( -1716. Once the manuscript has been located, in this article, our aim is to show and analyze this work of Ozanam, its content, its notation and its structure and how, through the new algebraic method, he not only solved and expanded the questions proposed by Diofante, but also introduced a connection between the algebraic solutions and what he called geometric determinations by obtaining loci from the solutions.