In the 16th century, Cardinal Niccolò Gaddi built a palace on the Montecitorio, a medieval debris hill near Piazza Colonna. In 1653, the palace was acquired by prince Nicolò Ludovisi. Gianlorenzo Bernini's design for the remodeling of the palace, based on a concave floor plan with two double apartments in the wings sharing a central sala and staircase, was subsequently partially built by himself and Mattia de Rossi. distance from Hotel Dei Borgognoni 50 ft
After Ludovisi's death in 1655, the works stopped. In 1694, the fragment was acquired by Innocent XII, who used it as the Curia Innocenziana. The palace's state at the time of the transaction is recorded by a view created by Carlo Fontana: only the right three window axis were completed, most of the piano nobile walls were up, but the portal zone missed entirely. The same state can be seen on a view of Piazza Colonna by Livinio Cruyl. Carlo Fontana and his son Francesco, who finished the palace, did not follow Bernini's original plan, which can be seen on a paiting by Mattia de Rossi, today in the Galleria Doria, in some points: Instead of a central portal and a serliana as a middle window (which recalls Palazzo Farnese, a triaxial portal zone inspired by a triumphal arch was created; instead of a balustrade with sculptures above the middle part, a high belltower was built. Bernini's bossage of the outer six window axis is, according to Roberto Pane, inspired by Michelangelo's "nonfinito" and was depicted by several theories of architecture like Domenico de Rossi's Studio d'Architettura Civile.
In 1871, the palace became parliament (Camera dei Deputati) , and the semicircular rear courtyard, built by Maderno, was given a roof. From 1908 to 1918, the interior of the palace was remodeled and a new facade on the Piazza del parlamento was created by Ernesto Basile.