Dvorak's Symphony No.9 or "Symphony from a New World" originally Symphony No. 5 is probably one of the most well known pieces of orchestral literature, everyone is familiar with the famous Movement II, the Largo.
The thing that Dvorak was most interested in at this point was folk melody which is the basis for this entire symphony, centering it around the pentatonic scale which he used to emphasize a more "folk like" feel and sound, and is also more American. The other unique and folk derived element of the symphony is his use of the modal scale (minor scale with a lowered 7) which was popularly used in Europeon music.
The Largo encorporates all of this, particularly a chant-like melody found in the English Horn!!! :)
To me, the opening of Movement II is similar to a processional with the solemn brass choir opening. The English horn is almost imitative throughout its solo portions of a chant which kind of makes sense, since one of Dvorak's main facisinations with the US was its negro spiritual and traditional music.