What is a canon?

21 March 2025, 09:32

You might be familiar with Pachelbel’s Canon in D – a popular choice of wedding piece often heard as the happy couple make their way down the aisle. But have you ever wondered what exactly a canon is?

Canons come in many forms, from simple rounds to more complex compositions that have continued to evolve over time. Here, we offer a brief introduction to canons and explore some of their unique characteristics.

What is a canon?

Let’s talk canons... a canon follows strict rules, an essence which is baked into its name. Whe word canon comes from the Greek kanōn, meaning ‘law’ or ‘rule’.

In music, a canon is a compositional technique where a melody is repeated by one or more voices or instruments, entering at different times to create a layered, interwoven sound.

(As a side-note, the word canon actually has two meanings in music: one refers to the technique we’re discussing, and the other refers to a collection of works considered essential or worth exploring – often called the canon of classical music.)

Some of our favourite childhood songs are canons – take ‘Row, Row, Row Your Boat’ for example. This is the simplest form of canon known as a round canon. The same whimsical tune repeats endlessly with each voice entering at different times, creating a playful circular effect. It can also be called an infinite canon because when you reach the end, you simply start again, continuing the loop.

Read more: What are the full lyrics, actions and origins of ‘Row Row Row Your Boat’?

How Pachelbel's Canon works

Which composers have written canons?

Another type of canon is the accompanied canon, and one of the most famous examples of this is the Canon in D by Baroque composer Johann Pachelbel. But what makes it an accompanied canon?

In Pachelbel’s Canon, the violins play the same melody, but each entry is spaced two bars apart, creating the round effect. Meanwhile, the bass line – an ostinato – provides a steady harmonic foundation, accompanying the violin melody. This combination of repeating melodies and a continuous bass is what makes it an accompanied canon.

Read more: How did Pachelbel’s Canon in D become the most popular wedding song?

The great Johann Sebastian Bach was a master of the canon form, using it to push the boundaries of musical creativity and expand the canonic repertoire. In works like The Goldberg Variations, Bach weaves intricate canons, where voices enter at different intervals, creating rich, layered textures.

In 1747, Bach composed a series of pieces for King Frederick II of Prussia, known as The Musical Offering, which includes a canon called the Crab Canon (watch below).

This canon features a melody played forwards, with the same melody played backwards accompanying it, creating a unique interplay between the two. Bach often left it up to the performer to figure out how the canon works, adding an extra layer of intrigue to the piece.

There have been a few unsubstantiated claims that Pachelbel’s Canon in D was in fact written for the wedding of Bach’s brother, Johann Christoph, in 1694, but this is fairly unlikely.

Bach - Canon a 2 Cancrizans from The Musical Offering BWV 1079 | Netherlands Bach Society

There are countless variations of canons (we could go round and round exploring them all...).

From the simple to the complex, composers will continue to experiment with this technique like they have done for centuries before.