There are some items which are mentioned in the exhibit, but are not on display. One of these items is an account bookwhich containas an entry for a key which Michelangelo had made for a chest.
Here is are a few excerpts from the USA Today article:
Going through their archives for an exhibit on the 500th anniversary of the basilica, researchers from the Fabbrica di San Pietro, the office where all documents concerning the running of the basilica are kept, came across an entry for a key to a chest "in the room in St. Peter's where Master Michelangelo retires."
"We now know that Michelangelo definitely had a private space in the basilica," Maria Cristina Carlo-Stella, who runs the Fabbrica, said in an interview with The Associated Press this week. "The next step is to identify it."
The ink-scripted entry contained in a parchment-covered volume listing the expenditures of the Fabbrica for the years 1556-1558, refers to the payment of 10 scudos to the blacksmith who forged the key, but offers no details about the chest or the location of the room.
A frescoed room with a cozy fireplace, part of the area in the left wing of the basilica where the archives are housed, had traditionally been called "la stanza di Michelangelo," Michelangelo's room.
"The theory is very romantic and conspiratorial, but totally unfounded," said Federico Bellini, an art historian who works in the archive department, as he pointed to a 16th-century sketch on his computer showing the state of the left wing during Michelangelo's time at the Vatican — a pile of rubble intertwined with vegetation.
Originally the Fabbrica, whose documents date from as far back as 1506, was in the right wing of the basilica, already built at the time of Michelangelo. It was known that artisans had been allotted lodgings there, leading experts to direct their search for Michelangelo's studio to that area.
This gives me just one more reason to want to visit this exhibit. If only I was in Rome!