How to Write a Theme
Many composers and songwriters run into the same problems when they are just starting out. They are often very good at coming up with ideas and getting started, but then they don't know what to do next. In this tutorial I'll show you how to take an initial idea and develop it into a theme.
From classical symphonies to contemporary video game scores, the great instrumental works of western music are driven by a powerful theme. A good theme can make people instantly recognize a franchise, associate a character with good or evil, and provide inspirational material for an entire composition.
We'll look at two basic ways an idea can be fleshed out into a full theme. Although they are somewhat formulaic in nature, you will be surprised how many times you hear these patterns over and over again once you know to listen for them.
When I talk about themes in this tutorial, I mean complete 8-bar melodies. Film music and opera often rely on leitmotifs, which are recognizable motives or musical ideas, but for our purposes those are too short to be considered fully formed themes.
In a recent tutorial I outlined 11 Ways to Find Immediate Inspiration for Your Next Composition. The main point was that if you give yourself a prompt, ideas will flow more easily.
In the case of writing a theme, your character, setting or story is the prompt. You can use that element to influence musical decisions.
For example, if you're writing a theme for a villain, you might want to choose a minor key. If he is very sneaky, perhaps you'll focus on small intervals like half steps and chromatic movement.
If you're writing for your hero you could start with a major key, use strong intervals like 4ths, 5ths and octaves, and have a very strong and forceful rhythm.
However you decide to create it, your opening idea is the most important part of your theme, and is generally the part people will recognize.
Once you have an opening idea, you can use either the "sentence" or "period" to flesh it out into a full theme.
The first pattern we'll look at is the sentence.
The basic pattern is main idea → repetition (exact or modified) → forward drive → cadence.
The first four measures will typically stay harmonically static, either just staying on the tonic chord or having very little forward motion.
The "continuation", as theorist William Caplin calls it, is when the theme picks up the pace and makes a forward drive toward the cadence.
Usually there is some sense of quickening which is achieved by fragmenting the melody into smaller chunks, increasing the harmonic rhythm (how quickly the chord changes happen), increasing the rhythmic activity, or a combination of all three.
The continuation drives us into a cadence which either feels resolved (such as an authentic cadence on I) or leaves us hanging unresolved (like a half cadence on V).
Let's look at two John Williams themes that use the sentence for their construction.
Yoda's Theme - Star Wars Episode V: The Empire Strikes Back
The theme begins with a two measure idea.
The basic idea repeats with just slight changes. First he fills in the gap between G and C, which gets the energy picking up slightly. Next the last two notes reach just a little higher.
Notice that although the melody reaches a bit higher, the harmony is still sitting statically on I. There is a little bit of striving, but we haven't actually achieved any sense of forward drive yet.
In measure 5 the melody fragments into smaller chunks, one measure statements instead of two. There is a sense that the energy is picking up, that the theme is starting to go somewhere.
Finally the theme comes to rest on back on the I chord. We get a moment to catch our breathe. Because the melody is on E and not the tonic C, it feels like it isn't fully complete which makes room for the next section to begin.
Flight to Neverland - Hook
Once again we start with a two measure idea.
Just like before, the repetition strives a little bit higher but the harmony remains grounded by the tonic in the bass.
At measure 5 we begin the forward drive towards the end. To pick up the energy he uses an increase in harmonic rhythm with the chords changing on every beat, but no increase in the melodic rhythm. It's the sudden activity in the bass that makes this feel like we're going places.
The cadence wraps it up and brings us back home. Notice how the authentic cadence on I with tonic in the melody makes the theme feel very complete. Also interesting to notice is that the theme started in B minor but ended on B major.
Like the sentence, the period begins with an initial two measure idea. However instead of repeating the idea right away, it is answered by a contrasting idea that leads to a half cadence.
The theme then returns to the main idea, and this time the answer leads to an authentic cadence.
These two halves are called an antecedent and consequent, and can be thought of as a question and an answer. The antecedent asks an open ended question, the consequent responds and answers it affirmatively.
You can see that a principal aspect of the period is balance, and for this reason you will often find it being used for slower themes or other types of pieces that are very sectioned and regular.
Here are two more John Williams themes, this time using the period for their construction.
Anakin's Theme - Star Wars Episode I: The Phantom Menace
Although this example is harmonically complex, don't pay much attention, the chords aren't what we are focusing on right now. What I want you to pay attention to is the melodic pattern and the balance of main ideas and contrasting ideas.
The theme begins with a two measure idea. Although the chords seem to change every two beats, there is a constant A in the bass. This tonic pedal keeps the theme grounded and feels like an opening statement because it's not yet "going anywhere" harmonically. Also the first and fourth chords are both A major, which encloses the whole idea around that one chord.
The opening idea is answered by a two measure idea that resolves to an A major chord with E in the melody. Coming back to A may seem final, but the E in the melody makes it feel incomplete and unresolved.
Notice that on measure 3 we have moved forward into new harmonic territory (a very strange F7/E!). Also interesting to note is that the basic idea goes up, and the answering idea comes back down.
This question-answer forms its own four measure question, which is then responded to in measure 5.
The response begins with a repetition of the basic idea, again over an A tonic pedal. Similar to what he did with his sentences, Williams stretches a little bit higher on the repetition but keeps the harmony the same.
The answering idea then serves the same function as it did in the antecedent; the melody comes back down and the harmony comes to a perfect authentic cadence on I. This time the melody lands on the tonic note A and the theme feels complete.
Star of Bethlehem - Home Alone
We begin with a two measure idea over tonic harmony.
An answering idea comes to a half cadence. The sense of "we're not done yet" is very easy to feel and hear in this theme because the melody is on 5 and the chord is V.
The consequent begins in the exact same way as the antecedent, but this time he only repeats the first measure and not the whole two measure idea. He uses measure 6 as a way to rise to a climax.
The consequent ends with a new answering idea which also modulates to a new key. Notice the pickup in harmonic rhythm which adds an extra "driving it home" feel. The chords start moving twice as fast which pushes us towards the perfect authentic cadence in E minor. Even though the key has changed, the overall feeling is one of completion.
Which to Use, Sentence or Period?
Which construction to use for your theme will depend on context and what comes naturally. Some ideas just automatically shape themselves into one mold or another.
As a general rule of thumb (with plenty of exceptions), the sentence is more open ended and the period more complete.
So the sentence is more suited to dramatic themes that want to keep growing and developing, while the period has a feeling of balance and is a good fit for slower or more restrained ideas.
It is likely not an accident that the exciting opening theme from Flight to Neverland is a sentence while the more romantic Anakin's Theme is a period.
Don't be discouraged by the idea of a "formula" restricting your creativity, and thus reject this process. The point is to understand the basic principles that make these themes work, so that you can have a strong foundation for expanding on them in your own creative ways later.
There are many exceptions and ways to break from these forms, consider them a starting off point for learning the basic technique before launching off into more complex themes.
And most importantly: when you have a good idea but find yourself stuck with what to do with it, see if you can follow one of these two basic patterns to turn that idea into a complete theme.