The construction of the various wings of Palazzo Colonna lasted for five centuries. This has led to the overlapping of different architectural styles, interiors and exteriors, which characterize and reflect the different periods. From 1300 to 1500 it acted as a family fortress. Oddone Colonna, elected Pope on November 11, 1417 under the name of Martin V, appointed the Palace as the Pontifical Seat and lived there from 1420 to 1431, the year of his death.
In those ten years, within the austere rooms of Palazzo Colonna, Pope Martin V designed and implemented a great plan for a cultural, urban and administrative rebirth of the city of Rome, which lay in devastating conditions after the period of papal exile to Avignon and the Western Schism. In 1527, during the sack of Rome by the troops of Emperor Charles V, Palazzo Colonna was one of the few buildings that was not destroyed due to the good relationship of the family with the Empire. Instead, it offered a safe haven for more than three thousand Roman citizens. Throughout the 1600s, the Palace took the form of a large Baroque palace at the will of three generations; the leading family members being Philip I, Cardinal Girolamo I and Lorenzo Onofrio, who relied on architects and artists of great skill and reputation. In fact, Gian Lorenzo Bernini, Antonio del Grande, Carlo Fontana, Paolo Schor, and many others, all lent their expertise.
Also during this time was the construction of the beautiful and majestic Galleria Colonna, which has 76 meters of length facing onto via IV Novembre. This authentic jewel of the Roman Baroque is now open to the public, with apartments of major artistic value that are most representative of the Palace. They house the Art Collections of the family, notified and bound by the fidecommesso of 1800, including masterpieces of absolute excellence painted by leading Italian and foreign artists between the XV and XVI century. Among the artists are Pinturicchio, Cosmè Tura, Carracci, Guido Reni, Tintoretto, Salvator Rosa, Bronzino, Guercino, Veronese, Vanvitelli and many others.