The Greek of the classical age, with Euclid and Archimedes, have conceived very next ideas to those that have allowed the invention of the Infinitesimal and Integral calculation. The author thinks how just Euclide has grazed the concept of infinitesimal, with his theorem related to the "horn angle." It was then in 1600 that Leibniz and Newton they created the Infinitesimal Calculus and that Integral. But the infinitesimals have always elicited criticisms for their logical contradictions, immediately stigmatized by the bishop Berkeley. With the method of the double limit of Weierstrass, the...