scientific institutions by the twenty years of Mussolini's rule. He became president of the Accademia dei Lincei until his death and was elected a member of the Académie des Sciences in Paris. On 5 December 1949, he became a life senator of the Italian Republic. Castelnuovo died at the age of 86 on 27 April 1952 in Rome. He is buried in the Verano cemetery, in Rome, together with his wife, Elbina Enriques Castelnuovo and his mathematician daughter, Emma Castelnuovo. Work In Turin Castelnuovo was strongly influenced by Corrado Segre. In this period he published high-quality work on algebraic curves. He also made a major step in reinterpreting the work on linear series by Alexander von Brill and Max Noether (Brill–Noether theory). Castelnuovo had his own theory about how Mathematics should be taught. His courses were divided into two: first a general overview of mathematics, and then an in-depth theory of algebraic curves. He has said about this approach: He also taught courses on algebraic functions and abelian integrals. Here, he treated, among other things, Riemann surfaces, non-Euclidean geometry, differential geometry, interpolation and approximation, and probability theory. He found the latter the most interesting, because as a relatively recent one, the relationship between the deduction and the empirical contribution was more clear. In 1919, he published Calcolo della probabilità e applicazioni, an early textbook on the subject. He also wrote a book on calculus, Le origini del calcolo infinitesimale nell'era moderna. Castelnuovo's most important work was done in the field of algebraic geometry. In the early 1890s he published three famous papers, including one with the first use of the characteristic linear series of a family of curves. The Castelnuovo–Severi inequality was co-named after him. He collaborated with Federigo Enriques on the theory of surfaces. This collaboration started in 1892 when Enriques was only a student, but grew further over the next 20 years: they submitted their work to the Royal Prize in Mathematics by the Accademia dei Lincei in 1902, but were not given the prize because they had sent it jointly instead of under one name. Both received the prize in later years. Another theorem named partly after Castelnuovo is the Kronecker–Castelnuovo theorem (1894): If the sections of an irreducible algebraic surface, having at most isolated singular points, with a general tangent plane turn out to be reducible curves, then the surface is either ruled surface and in