Mamiani della Rovere, COUNT TERENZIO, born in 1800 at Pesaro, took a prominent part in the futile outbreak at the accession of Gregory XVI., and was compelled to flee to Paris, whence he returned to Rome in 1848 after the unconditional amnesty of Pius IX., and actually held office for three months in the papal ministry. He next withdrew to Turin, where he founded, with Gioberti, his famous society for promoting Italian unity. On the flight of Pius IX. from Rome to Gaeta he re-entered the political arena, and was for a short period foreign minister in the revolutionary cabinet of Galetti. On the fall of Rome he retired to Genoa; in 1856 he was returned member of the Sardinian parliament, and in 1860 entered Cavour's ministry as minister of Instruction. He was appointed ambassador to Greece in 1861, to Switzerland in 1865, and died at Rome, 21st May 1885.
Among his writings are Del Rinnovamento della filosofia antica Italiana (1836), Poeti dell' Età media (1842), Del Papato (1851), Confessioni d'un Metafisico (1865), Teorica della Religione e dello Stato (1868), La Religione dell' Avenir (1879), besides books on special social and philosophical problems, and treatises on various subjects. See his Life by Gaspari (1887).