 Immersed in the university 's violent gang culture , in 1947 he took part in a quashed attempt to invade the Dominican Republic and overthrow the military junta of Rafael Trujillo . Returning to student politics , Castro was involved with violent demonstrations in which protesters clashed with riot police , at which he became increasingly left @-@ wing in his views . Traveling to Bogotá , Colombia , he fought for the Liberals in the <unk> before returning to Havana , where he embraced Marxism . In 1948 he married the wealthy Mirta Díaz Balart , and in September 1949 their son Fidelito was born . Obtaining his Doctorate of Law in September 1950 , he co @-@ opened an unsuccessful law firm before entering parliamentary politics as a Partido Ortodoxo candidate . When General Fulgencio Batista launched a coup and overthrew the elected presidency , Castro brought legal challenges against him , but as this proved ineffective , he began to think of other ways to oust Batista . 
