Manzoni was a bibliographer of European reputation; he was also a patriot and fought in the first war of Independence (1848-49). He was then appointed minister of finances of the Roman Republic (1849).
He was banned from the Kingdom of Sardinia because of his republican ideals; he subsequently lived in London and in Paris. In 1854 he was allowed to return to Italy provided he did not get involved into politics. Once back in Lugo, following its annexation to Piedmont, he devoted himself to his studies.