Palazzo Colonna historical timeline

One family, one address, eight hundred years — and a cannonball nobody swept up.

Chronology

1. 13th century — the first part of the palace is built. Structural impact: the site on the slope below the Quirinal is taken, and never given up. What you see today: the oldest fabric, in the wing that now carries the Princess Isabelle apartments.
2. Over twenty generations — the palace belongs to the Colonna family continuously. Structural impact: each generation adds rather than replaces, which is why the house is a sequence of periods instead of one. What you see today: a private palace, not a museum that was once one.
3. Mid-1600s — Cardinal Girolamo I Colonna and his nephew Lorenzo Onofrio commission the Great Hall, designed by Antonio del Grande and later integrated by Bernini, Schor and Fontana. Structural impact: a gallery is driven through the house at its grandest scale. What you see today: the room itself.
4. 1700 — the Great Hall is inaugurated, by Philip II in the gallery's own account. The reference work instead gives the main gallery as completed in 1703. Structural impact: none to the fabric; the two sources differ on when it was finished. What you see today: a finished room and an unresolved date.
5. 1849 — during the Roman Republic, French forces under General Oudinot shell the city and a cannon ball lands on the short flight of stairs leading to the Great Hall. Structural impact: a hole, and a decision not to repair it away. What you see today: the ball, still lying where it stopped.
6. 1953 — the ending scene of Roman Holiday, with Audrey Hepburn and Gregory Peck, is shot in the gallery. Structural impact: none. What you see today: a room a great many people recognise without knowing why.

• Official website
• Wikipedia