In the 19th century, Nisida was the site of an infamous Bourbon prison that gained notoriety when - after a visit to the prison in 1851 - William Ewart Gladstone wrote his "Two Letters to the Earl of Aberdeen on the State Prosecutions of the Neapolitan Government", exposing the harsh conditions. In these letters, Gladstone coined the now famous description of the Kingdom of Two Sicilies as "the negation of God erected into a system of Government." Indignation throughout Europe was partially responsible for the at least partial improvement of the conditions in the prison.