The church takes its name from the chains (vincoli) proudly clasped in the coffer with bronze doors under the high altar. According to tradition they are the chains used to bind St Peter while he was held captive in the Mamertine prison (remnants of which are preserved under the church of San Giuseppe near the Forum). Part of the chains found their way to Constantinople, while the rest were housed in San Pietro by Pope Leo I (who had the church specially reconstructed from a 4th-century building for the purpose). When the two parts were eventually reunited, they are said to have miraculously fused together.
It was built in the fifth century (about 442) at the request of the Empress Eudossia, then rebuilt under Adrian I, in about 780. The doorway was added in the sixteenth century. At the beginning of the eighteenth century, Francesco Fontana had ionic bases added onto the 20 antique doric columns of the nave (which came originally from a Roman temple).
One of Michelangelo's masterpieces - Moses - is in the right transept. The majestic sculpture of a patriarchal Moses receiving the Tablets of Stone was originally designed as part of a 42-figure ensemble for the tomb of Julius II. Michelangelo spent years scouring the Carrara mountains for suitable pieces of stone, but the project never came close to completion, and he was to describe the work as 'this tragedy of a tomb'; much of his time was instead spent (reluctantly) on the Sistine Chapel.
Other artworks in the church are the Byzantine mosaic St Sebastian (c. 680), the monument to the Pollaiuolo brothers (c. 1498) by Luigi Capponi, and the tomb of Cardinal da Cusa (1464), attributed to Andrea Bregno. In the Sacristy is the Liberation of St. Peter by Domenichino.
You can find more information on San Pietro in Vincoli in the Wikipedia.
Recommended viewing from the collection:
The Web Gallery of Art contains 7 images of artworks from the San Pietro in Vincoli.