 Prior to the 17th century, a palace had been erected for the Cardinal Ferrero during the reign of Pope Sixtus V. The Pope Clement XII (Corsini) commissioned the present palace from Ferdinando Fuga, and it was completed in 1737 to house the secretariat of the "Sacra Congregazione della Consulta" (which served as the main council of state of the Papal states and tribunal) as well as the "Segnatura dei Brevi", as well as two corps of Papal Guard units.From 1798 to 1814, the palace was used as the Prefecture of Rome.In 1849, during the Roman Republic, it was the home of the ruling Triumvirate.