Mar. 08, 2006 (CWNews.com) - With the Swiss Guard celebrating its 500th anniversary, the Vatican will open a remarkable exhibit on the history of the renowned military unit on March 29.

The centerpiece of the exhibit, which will be held in the colonnade on the left wing of St. Peter's Square, recalls the most storied moment in the history of the world's oldest military force: the defense of Pope Clement VII during the sack of Rome in 1527. The Swiss Guard took a defensive stand that allowed the Pontiff to escape from the Vatican through the passetto that still links the apostolic palace to the Castel Sant' Angelo, where he took refuge. Only 42 members of the Swiss Guard survived that battle; 147 were killed.

The exhibit in St. Peter's Square includes the military armor of Emperor Charles V, who ordered that attack on Rome. Also included is the sword of Pope Julius II, who was an active military leader as well as the patron of Michelangelo.

It was Pope Julius II who established the Swiss Guard, recruiting 200 soldiers from Switzerland. The papal bull ordering those men recruited is still preserved at that Vatican, and forms an important part of the exhibit, along with the flags that Pope Julius sent to Switzerland in thanks after the soldiers arrived. The first members of the Guard reached the Vatican in dramatic fashion, arriving on foot on January 22, 1506, after having marched across the Alps in wintertime. The exhibit includes portraits, documents, and commemorative stamps and coins from throughout the history of the Swiss Guard. Many of the items that will be on display are from the Vatican's own collection, including the private archives of the Swiss Guard. (For the first time the public will be able to see the Guard's own portraits of every commander who has served during its 500-year history.) There will also be items on loan from collections elsewhere in Europe.

One such item is a triptych that Pope Clement VII kept in his private apartment in the apostolic palace, until it was stolen by marauding soldiers during the sack of Rome. The triptych is now in the permanent collection of the cathedral in Caligari, Italy; it will be returned to Rome for the first time in nearly 480 years.