Marcello’s Oboe Concerto in D minor featured a simple, singing melody.

Today, it is a staple for pianists and is frequently featured on "relaxing classical" playlists, often stripped of its outer fast movements. 2. The Keyboard Concerto Adagio (BWV 1056)

While Johann Sebastian Bach never wrote a standalone "Adagio" in the modern sense of a single-movement pop-classical hit, the label "Adagio - Bach" has become a globally recognized shorthand for some of his most profound slow movements. Often these pieces are transcriptions of other composers' work or movements pulled from larger concertos, distilled into moments of meditative silence. 1. The "Bach-Marcello" Adagio (BWV 974)

Bach added intricate, "filigree" ornamentation—turns, trills, and passing notes—that transformed a straightforward tune into a masterpiece of Baroque expression.

The most famous "Bach Adagio" is actually an arrangement. Around 1715, Bach transcribed an oboe concerto by the Venetian composer Alessandro Marcello for solo keyboard.

Another contender for the "Adagio" title is the middle movement of the Harpsichord Concerto No. 5 in F minor .