Sant'Ivo alla Sapienza, a church with a courtyard designed by Baroque artist Borromini and later home to Italy's state archives, hosts the show until May 15.
Curators told reporters at a news conference Thursday that one document on display features a drawing done by a judge of a sword and dagger seized from Caravaggio, who was arrested for carrying weapons without proof of permit.
Also plucked from the archives is a document of a lawsuit by another painter against the often-ill tempered Caravaggio, who lived from 1573 until 1610.
On display is a portrait of Paul V, the early 17th-century pontiff from the Borghese noble family in Rome. The pope lifted a death sentence against Caravaggio after he fled Rome in 1606 for killing a man in a duel.
The painting, attributed to Caravaggio, is from the private collection of the Borghese noble family, and was last shown in public 100 years ago, in Florence.
Curators selected for the exhibit paintings by artists who had at some point been mentioned by Caravaggio and described by him as being among the "bad ones and good ones," said Eugenio Lo Sardo, head of the Italian state archives.
That means visitors will "be able to understand the artistic tastes of Caravaggio," who thus becomes "your guide to the exhibition," Lo Sardo told AP Television News.
The artist is celebrated for his innovative use of "chiaroscuro," a technique in which illuminated figures dramatically stand out against dark backgrounds.
AP reporter Valentina Chiarini contributed to this report.