Palazzo Venezia was begun in 1455 for the Venetian cardinal Pietro Barbo. It was enlarged when the cardinal became Pope Paul II (r. 1464-72). The design of the palazzo has been ascribed to Leon Battista Alberti (1404-72) and to the little-known Francesco del Borgo (c.1415-68).
In the 16th century Palazzo Venezia was given to the Republic of Venice for its embassy. Centuries later, it was occupied by Benito Mussolini, who used the grand Sala del Mappamondo as his office. It was from the balcony facing Piazza Venezia that Italy's Fascist dictator would make many of his speeches.