This slow and solemn March comes from the Funeral Music for Queen Mary by Henry Purcell. It was composed for the funeral of Queen Mary II and was also played at Purcell's own funeral the following year when he died at the age of 36. The original music was for 4 trumpets, and probably accompanied by a drum (which can be considered as an optional instrument). Here the score is laid out for 3 trumpets in B-flat and a trombone, and the links on the left allow you to download the sheet music in PDF format or as MIDI or MP3 files. This music was arranged by the composer Wendy Carlos for the film "A Clockwork Orange", and here is an arrangement of the music for Piano or Keyboard.
The audio controls below allow you to play the mp3 version of Purcell's March from the Funeral Music for Queen Mary (score) or you can download the MP3 file. You can also download the midi version of Purcell's March from the Funeral Music for Queen Mary (score).
The image below is the first page of the sheet music, and here you can download the full sheet music for Purcell's March from the Funeral Music for Queen Mary (score) in PDF format.