The Instituto de Enseñanza Secundaria San Isidro (IES San Isidro) is a co-educational day school for pupils from 12 to 18 years of age. It is located in the historical Calle de Toledo in Madrid, Spain. San Isidro has educated eight Spanish prime ministers and was formerly referred to as the "nanny" of Spain's statesmen. With the discovery of the Americas, the school gained importance in educating young men who would later become a credit to the Spanish Empire. It has four Nobel Prize laureates among its alumni: José Echegaray, Jacinto Benavente, Vicente Aleixandre, and Camilo José Cela.