The main gallery,completed 1703, and the masterful Colonna art collection was acquired after 1650 by both the cardinal Girolamo I Colonna and his nephew the Connestabile Lorenzo Onofrio and includes works by Lorenzo Monaco, Ghirlandaio, Palma il Vecchio, Salviati, Bronzino, Tintoretto, Cortona, Annibale Carracci (painting of The Beaneater), Guercino, Albani, Muziano and Guido Reni. Ceiling frescoes by Filippo Gherardi, Giovanni Coli, Sebastiano Ricci, and Giuseppe Bartolomeo Chiari celebrate the role of Marcantonio II Colonna in the battle of Lepanto (1571). An Apotheosis of Martin V was painted by Benedetto Luti. There are frescoed apartments completed after 1664 by Crescenzio Onofri, Claude Lorraine and Pieter Mulier (nicknamed Cavalier Tempesta). Other rooms were frescoed in 1700s by Pompeo Batoni and Pietro Bianchi.

The older wing of the complex known as the Princess Isabelle's apartments, but once housing Martin V's library and palace, contains frescoes by Pinturicchio, Antonio Tempesta, Onofri, Giacinto Gimignani, and Carlo Cesi. It contains a collection of landscapes and genre scenes by painters like Lorraine,Caspar Van Wittel (Vanvitelli), and Jan Brueghel the Elder.

Along with the possessions of the Doria-Pamphilij and Pallavacini-Rospigliosi families, this is one of the largest private art collections in Rome.

via delle pilotta 17 (palzzo colonna)