Palazzo Venezia
The Palazzo di Venezia (formerly Palace of St. Mark) is a palazzo (palace) in central Rome, Italy, just north of the Capitoline Hill. The original structure of this great architectural complex consisted of a modest medieval house intended as the residence of the cardinals appointed to the Church of San Marco. In 1469 it became a residential papal palace, having undergone a massive extension, and in 1564, Pope Pius IV, to win the sympathies of the Republic of Venice, gave the mansion to the ambassadors of La Serenissima on condition that a part of the building should be kept as a residence for the cardinals"the Apartment Cibo"and that the Venetian Republic should provide for the building's maintenance and future restoration. The palazzo faces Piazza Venezia and Via del Plebiscito. It currently houses the National Museum of the Palazzo Venezia.

History
It took on a new layout when, in 1451, Pietro Barbo, son of one of the sisters of Pope Eugenius IV, became cardinal. It was a fortified building, composed of a half-basement and a mezzanine that functioned as a piano nobile, extending over a small area between the basilica and the gate of the present palazzo overlooking the piazza, with a small external tower. It was a building of no exceptional size but was sufficiently dignified as a cardinal's residence so that, even in 1455, Pietro Barbo could proudly boast of it, having a commemorative medal struck in its honor. In 1455, the building manifested some of the first Renaissance architectural features in Rome; although the overall aspect is of a massive, defensible medieval structure with battlemented crown. It was built around the medieval tower at the right of its facade and incorporated within its mass the ancient Church of San Marco founded by Pope Marcus in 336 and dedicated to the Evangelist who would become protector of Venice, completely rebuilt in 833 and often modified since. Much of the stone to build the palazzo was quarried from the nearby Colosseum, a common practice in Rome until the 19th century. The design is traditionally attributed to Leone Battista Alberti, the Venetian cardinal, Pietro Barbo, who later became Pope Paul II was the patron: he continued to inhabit it even as pope. The project was continued after his death by his nephew Marco Barbo, patriarch of Aquileia. The green courtyard had only been enclosed by a colonnade surmounted by a loggia for less than a quarter of its full ranges before work was interrupted; the fully Renaissance design was by Giuliano da Maiano. The building became a papal residence, and in 1564 Pope Pius IV gave use of much of the building to the Republic of Venice for its embassy and for the titular cardinal of S. Marco, by tradition always a Venetian. From the Treaty of Campoformio (1797) throughout the nineteenth century, as Austria succeeded the defunct Republic, the building was the seat for the Austrian ambassador to the Vatican. In 1916, Italy, at war with Austria-Hungary, seized the building. It was subsequently restored. Benito Mussolini had his office in the Sala del Mappamondo, and used a balcony in the palazzo for delivering many of his most notable speeches, such as the declaration of the Italian Empire, 9 May 1936, to crowds gathered in the Piazza Venezia below. The Museo del Palazzo di Venezia, housed in the building, contains galleries of art, predominantly pottery, tapestry, statuary from the early Christian era up to early Renaissance.