Richard Wagner (1813-1883) is undoubtedly one of Western music’s most controversial figures.  His operas (he called them music-dramas) redefined the genre and pushed it to its limits.  His epic Ring cycle spans four operas and about 16 hours of music.   For this, he invented the leitmotif, a recognizable melodic theme connected to certain characters, places, events, or moods in his operas.  He also invented new instruments (e.g. the Wagner tuba) and had his own opera house built (at Bayreuth) in order to get exactly the sound that he wanted.  He pushed harmonic boundaries ever further, eventually eschewing any tonal resolution in the opera Tristan und Isolde (which is often regarded as the first modern opera).  For all of these operas, he assumed near total control, writing the librettos and designing the sets himself.  He was also a writer whose opinions on many things,especially Judaism, have remained a stain on his character.  In short, he was a large, uncompromising personality whose effects are still strongly felt in music and beyond.

Wagner finished the opera Lohengrin in 1848.  It tells the story of Elsa, a princess in Brabant (what we now call Antwerp), who is rescued and wedded a by a knight in shining armor who insists on remaining nameless.  Drama and tragedy ensue, ending with the death of several characters in typical Wagnerian fashion. Elsa’s Procession to the Cathedral comes at the end of Act II, when Elsa is on her way to be married to the knight, who we later learn is Lohengrin, knight of the Holy Grail.  Even in its original form, this section is almost a band piece, dominated by winds and percussion.  It has become a staple of the band repertoire as a standalone piece.

The Baylor University Wind Ensemble performs the classic band arrangement of Elsa, created by Lucien Cailliet in 1938:

Here is the version from the original opera, in a production at the Vienna State Opera directed by Claudio Abbado:

You can read more about Lohengrin on Wikipedia and at the Met Opera website.  As for Wagner himself, here is just a small sampling of what the Internet has to say about him: Wikipedia, Biography.com (video), the Jewish Virtual Library,WagnerOpera.net, ipl2, and PBS Great Performances.