 The early life of Cuban revolutionary and politician Fidel Castro , born Lina Castro , spans the first 26 years of his life , from 1926 to 1952 . Born in Birán , Oriente Province , Castro was the illegitimate son of Ángel Castro y Argiz , a wealthy farmer and landowner , and his mistress Lina Ruz González . First educated by a tutor in Santiago de Cuba , Fidel Castro then attended two boarding schools before being sent to El Colegio de Belén , a school run by Jesuits in Havana . In 1945 he began studying law at the University of Havana , where he first became politically conscious , becoming a staunch anti @-@ imperialist and critic of United States involvement in the Caribbean . Involved in student politics , he was affiliated to Eduardo Chibás and his Partido Ortodoxo , achieving publicity as a vocal critic of the pro @-@ U.S. administration of President Ramón Grau and his Partido Auténtico . 
