Quatrain poems are divided by sections, or stanzas, containing four lines each. This type of poetry is generally rhymed, though not always, and can adhere to any metric form. Different styles of quatrain poems include ballad, heroic, rhyme enclosure, triple, double couplet and unrhymed. The quatrain has been a popular poetic form for many influential writers, such as Samuel Taylor Coleridge, William Shakespeare and Nostradamus.
A textbook example of quatrain poetry can be found in William Blake’s The Sick Rose:
O Rose, thou art sick!
The invisible worm,
That flies in the night,
In the howling storm,
Has found out thy bed
Of crimson joy;
And his dark secret love
Does thy life destroy.
Rhymed quatrain poems can adopt different patterns, many of which are identified by specific, descriptive names. "The Sick Rose," for example, is written in ballad form. Ballad quatrains are normally constructed in an ABCB pattern, in which the second and third lines of a stanza rhyme, while the first and third do not.
Other categories of quatrain poems are similarly named and described by their rhyming patterns as well. The heroic quatrain uses an ABAB pattern. A quatrain with rhyme enclosure uses an ABBA, sandwiching a rhyme between the rhyming first and fourth lines of a stanza. A triple quatrain uses an AABA pattern, in which there are three rhymed lines, and a double couplet uses an AABB pattern. Not all quatrains are written with a rhyming pattern, however. For example, Scottish poet Frank Kuppner made a career of writing unrhymed quatrain poems.
One of the most popular and enduring forms of quatrain poetry is the Shakespearean sonnet, also called the English sonnet. These poems consist of three quatrain stanzas followed by a couplet. Shakespeare made this style famous, but many other poets have adopted the form. Perhaps the most famous English sonnet is one written by Shakespeare himself, Sonnet 18. The sonnet begins with the famous line, "Shall I compare thee to a summer's day?"
Although the stanzas in an English sonnet are primarily written in iambic pentameter, it isn't necessary for quatrain poems to use one metric form over another. In fact, just as one can write unrhymed quatrains, one could also write quatrains that don't follow any particular metric pattern. The only rule necessary to write a quatrain is to have four lines per stanza—the rest is up to the poet.