If you're looking for sources regarding this piece, Andre M. Smith published an article in the May 1994 edition of the International Trumpet Guild Journal about the history of Ewald's four brass quintets. According to the article, this piece was indeed written first as a brass quintet but was considered unplayable at the time and then reworked as a string quartet.
TrumpetMan202 13:43, 20 June 2011 (UTC)
