The English horn is related to the oboe and has a larger bore and is longer. Unlike the oboe, it is a transposing instrument, sounding a fifth lower than where the music is written.Why it is called an English horn is a mystery. It’s origin has nothing to do with England. It is also sometimes called a cor anglais, a French name, but it has nothing to do with France either. Made of wood, the English horn uses the same fingering system as the oboe, so it is often what musicians refer to as a “double”, meaning that oboists also “double”, i.e. play the English horn as well.
It has been a standard member of the symphony orchestra since the Romantic composers began including it in their musical compositions. While there are instances of its use in the mid 1700s, it really came into its own in the 1800s.
Hector Berlioz included the English horn in Symphony Fantastique, which was written in 1830. One of the most famous English horn solos is the “Going Home” theme from Dvorak’s New World Symphony. http://www.youtube.com/watch?v=FXTKtC2eCAM
If you have some extra time, check out this performance of Ravel’s Rapsodie Espagnola,http://www.youtube.com/watch?v=SqDD4vjZJfw&feature=related , a remarkable rendition by the DePaul Symphony Orchestra. The English horn solo happens at about 6:57.