Italian politician, born in 1806 in Sonnino, and died in Rome in 1876. During the pontificate of Gregory XVI was responsible for the administration of the Papal States as Treasurer general, task that played in a quite opposite to liberalism line. The successor of Pope Gregory, Pope Pius IXappointed him Cardinal in 1847 and Antonelli participated actively in the political life of his pontificate.
When Pellegrino Rossi was killed in November 1848, the Pope had to flee Rome and Antonelli accompanied him into exile. Later Pius IX appointed him Secretary of State. After the fall of the Roman Republic, on July 4, 1849, came the return of the Pope to Rome (April 12, 1850), and from then until about 1870, Antonelli played a prominent work in the politics of the Papal States as Minister of Foreign Affairs, who served until his death. In that capacity, he/she was declared hostile to any kind of liberal reform and considered impossible to reconcile the temporal power of the Pope with a constitutional Government. It fostered a policy of rapprochement with the France of Napoleón III, imposed on the antibonapartista direction of his opponents, among whom was F. De Merode.