Starting in 1949, Dalí spent his remaining years back in his beloved Catalonia. The fact that he chose to live in Spain while it was ruled by Franco drew criticism from progressives and many other artists. As such, it is probable that at least some of the common dismissal of Dalí's later works had more to do with politics than the actual merits of the works themselves. In 1959, André Breton organized an exhibit called, Homage to Surrealism, celebrating the Fortieth Anniversary of Surrealism, which contained works by Salvador Dalí, Joan Miró, Enrique Tábara, and Eugenio Granell. Breton vehemently fought against the inclusion of Dalí's Sistine Madonna in the International Surrealism Exhibition in New York the following year.
Late in his career, Dalí did not confine himself to painting but experimented with many unusual or novel media and processes: he made bulletist works and was among the first artists to employ holography in an artistic manner. Several of his works incorporate optical illusions. In his later years, young artists like Andy Warhol proclaimed Dalí an important influence on pop art. Dalí also had a keen interest in natural science and mathematics.