A fairly common practice in the Baroque era was for organists (especially the great J. S. Bach) to borrow" and transcribe orchestral music from themselves or other composers to create spectacular organ solos. Bach adapted several works by Vivaldi such as this Concerto in D "Grosso Mogul" originally for solo violin and strings. The organ and brass pass the musical material between them and sometimes double at the octave to create a powerful effect. This transcription is the opening Allegro movement only. (6:40)