Music is such a part of the film or television experience that we often take it for granted. In the earliest days of cinema, before the actors had voices, movies had music, very often played live. Music in movies has always helped to tell a story, because music has always been that thing that speaks when words just won’t do.
Music is a language, and movie and television music is a language we all know very well. We know to be tense at the low rumble of cellos, to laugh at a bouncy bass solo, to be thoughtful when we hear a wistful wood wind. And we know when a particular melody plays, that this is a moment for our special character. That is, we know what theme music is.
But where did theme music come from? You might be surprised to know that it’s a relatively new invention in the history of western music. Up through was is known as the “classical” period, which culminated in Mozart’s music and ebbed away in the early 19th century, the idea of a certain character being associated with a certain song or melody in say, an opera (one of the most popular entertainments of the era) was all but unheard of. Even in instrumental music, a certain melody could recur as a theme, but it didn’t necessarily “mean” much beisides maybe “triumph” or “dundundunDUN!”
The idea, or should I say idee (I promise that pun will make sense by the end of this paragraph), that a melody could help tell a story, that it could truly be a theme, took it’s first major steps with a guy named Hector Berlioz. Berlioz was many things: talented, dramatic and a little bit nuts (he initially wanted to study medicine, not music, but was so disgusted the first time he saw human remains, that he jumped out a window). The work which got him a lot of attention, and cemented his place is music history was the Symphonie Fantastique which premiered in 1830 (the beginning of the “romantic” era in music) in Paris. it was revolutionary because it was a symphony with a plot. A young man becomes obsessed with a woman, takes some opium and has some crazy hallucinations about her, yada yada (of course this was based on Berlioz's own obsession with an actress). The story was printed in the program, but the woman was represented by one recurring melody at evolves and repeats all through the work, Berlioz called this the idee fixe (the fixation).
The trick of using an melody to represent a thing didn’t really take off after Berlioz though. It took another composer to expand of the idea with truly epic and far reaching results. The same composer that gave us The Ride of the Valkyries. That’s right, Richard Wagner.
Richard Wagner, who many know only as the viking music guy that Hitler liked, is actually probably the person most responsible for making the music we hear in movies, and even just in life, what it is today. He was a jerk, but he was also a genius. Wagner LOVED the idea of theme music, or as he called them Leit Motifs. He began to use them in his early operas and soon they were the defining feature of his work.
Wagner was a master at assigning specific fragments of melody, or even specific chords, to characters and ideas. The way his motifs would merge and change would tell the story of his operas through the music, reinforcing the lyrics. For instance, in Das Rheingold, the first opera is in the super-epic Ring Cycle, there is a specific motif for the Rheingold (the magical gold hidden in the Rhine river). There's another theme when the evil dwarf Albrecht renounces love and takes the gold. These two themes combine later to make the theme for the Ring itself and recur through out all 15 hours of opera that follow.
Wagner was really good at using motifs, and really good at a lot of other things (like using chromatics and dissonance in new ways) and this had a huge influence on most of the western composers that followed him. Eventually, using motifs as storytelling became very common and those composers, along with Wagner influenced the composers of film scores to this day, because this was just another addition to the story. I'd challenge to yo listen to Antonín Dvořák's "New World Symphony" without hearing everything John Williams has ever written.
So, next time you hear "Hedwig's Theme" remember that the idea to write a theme has it's first original with a over-dramatic french guy and was perfected by a philandering, asshole German. And then maybe give Tristan und Isolde a listen.