The well known Adagio in G Minor from the italian composer Tomaso Albinoni (1671-1751) is actually a XX century piece... composed by Remo Giazotto (1910-1998), Italian musicologist, he composed this adagio on 1958 based on a melody found in a manuscript attributed to Tomaso Albinoni. Actually the manuscript was just a fragment of an Albinoni sonata that he had received from the Saxon State Library after the Second World War. The fragment has never appeared in public; Giazotto stated that it contained only the bass line, and the work was copyrighted by Giazotto.
So this piece has a weird story behind, but anyway it has been used in many films, television programmes, advertisements, recordings, and books. The piece is most commonly orchestrated for string ensemble and organ, or string ensemble alone. Here the transcription for organ solo.