How iambic pentameter really works

And why it works so well in English

Hamlet in the Queen’s Chamber (1857), William Salter Herrick

If you went to school in an English-speaking country, you’ve probably encountered the phrase iambic pentameter before, most likely in the context of Shakespeare’s plays or sonnets. Perhaps you even have some fond — or not so fond — memories of reading pentameters aloud in front of a room full of staring peers.

But, just in case you’re not acquainted with iambic pentameter, it’s the metre (or poetic rhythm) that is most closely associated with Modern English verse.

The majority, if not the vast majority, of English poems since the Modern English period began have been written in iambic pentameter.¹

Iambic pentameter is based on decasyllabic metre, which was traditionally used in French and Italian poetry. It was introduced to English by Chaucer (although the story is a lot more complicated than that — a topic for another day), and evolved into a metre that works exceedingly well with the English language, for largely linguistic reasons.

During the centuries that it held sway, iambic pentameter gave us the greatest works of Chaucer, Shakespeare, Milton, and many others.

Sadly, in recent years, iambic pentameter has fallen out of favour, and it’s acquired a reputation as fussy and overly strict.

But this is based on a misunderstanding. Iambic pentameter is much more flexible than its reputation suggests. The problem is that many people just don’t understand how it really works.

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Metre

To understand how iambic pentameter works, we need to understand “organized rhythm”, or metre.²

Metre is language organized in a particular way. And, because there are many ways to organize language, there are many possible metres.

You can think of a particular metre as a set of rules for determining whether a chunk of language is in or out. If the chunk of language follows the rules, it’s in: it counts as metrical, and you can put it in a poem. If it doesn’t, well, there’s the door.

The rules typically work by counting, or measuring, things. This makes sense given the etymology of the word metre, which comes from the Greek μέτρον métron, meaning ‘rule, measure.’

The fundamental thing to understand about most Modern English metre is that it’s accentual-syllabic in nature. This means it counts both accents and syllables.

Other languages’ metres care about different things: Ancient Greek metre tends to care about the length of vowels and whether syllables end in consonants. Old English metre cares much more about the number of accents than the number of syllables. Many Chinese metres care about both syllables and tones.

But Modern English metre tends to care about both how many accents are in a line and how many syllables.

Accent, or stress, refers to the degree of prominence that a syllable bears. I’ll be using stress and accent interchangeably in this article.³ But, whether you call it stress or accent, it’s surprisingly hard to define rigorously — in English, it correlates with higher pitch, longer length, and louder volume — but it’s easy to hear.

If you don’t know what I mean, try saying these words out loud: ábacus, banána, disappéar. Or listen to me say them below.

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Although each of these is a three-syllable word, the accent falls on a different syllable within each. Ábacus has stress on this first syllable, banána on the second, and disappéar on the third.⁴ If you try a word’s natural pattern with that of another word, it sounds… weird:

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By the way, I’ll be úsing the convéntion of displáying the locátion of a word’s stressed sýllable with an acúte áccent óver the sýllable’s main vówel throughóut this árticle. When the word is just one sýllable long, there’s no need to mark the stress, as there’s only one place it could be.

The existence of this stress accent is the raw material that most English metres work with, and iambic pentameter is no exception.

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Iamb to the slaughter

I’ve spent a lot of time discussing stress today, and for good reason. This metre works with English stress and fits it like a glove.

But what, you ask, does iamb mean? Good question.

An iamb is a sequence of two syllables, arranged like so: weak-strong. In English, strong means stressed, and weak means unstressed. Words like attáck are iambs, as is decíde. We use the symbols x and / for weak and strong, respectively.

Pentameter means simply five of something, all in a row. Iambic means that “something” consists of iambs. By the way — you may have noticed — all this explanation is iambic, and pentameter to boot.

Dispensing with the metre for a while — oops, still iambic. So is that. Okay, for real this time, let’s write the rest in prose.

Starting now.

(You see how easily iambic metre comes when you’re writing English prose?)

In case my metrical explanation was a bit obtuse, an iamb is a grouping of two syllables in a particular order: unstressed-stressed. Or rather, it’s an ordering of unstressed-stressed in English metre, because English is an accentual metre, that is, a metre that cares about where the accents (or stresses) of words are placed.

These two syllables together form a metrical foot, which is a name for a unit of metre larger than the syllable. There are other feet with their own fancy names, but iambs are the feet we’ll be most concerned with.

The origin of the iamb is in classical Greek metre, where it had a different meaning, since Greek metre is quantitative — cares about longs and shorts — rather than accentual.

In Greek metre, an iamb is a sequence of short-long, rather than unstressed-stressed. For this reason, we can generalize the idea of an iamb to mean a weak-strong sequence, where what is weak and what is strong depends on what kind of thing the metre cares about. But enough comparative poetics!

Why did I say that iambic metre fits English like a glove?

Some words are naturally iambic in English, many of which are verbs: attáck, revérse, ascénd, forgíve.

But you can also make iambs out of combinations of words, as long as the first one is unaccented and the second is accented: a cár, to bé, has góne, etc. You can also make iambs out of parts of words: baná- | -na splít is two iambs, even though neither of the two words is an iamb on its own.

If we want to use a more explicit way of marking the accent, we can use a two-tier system of notation, where the word is written below, and the level of stress is marked above: / marks a stressed syllable, and x marks an unstressed syllable:

x  /     x /     x  /     x  /
attack, reverse, ascend, forgive

Each of these x / sequences makes an iamb.

That’s the iambic side of iambic pentameter dealt with. Now let’s turn to the pentameter side: pentameter just means that each line consists of five metrical feet of whatever kind. In our case, the foot is an iamb, so the full line looks like this, with foot boundaries marked with ‘|’:

x  /  |  x  /  |  x  /  |  x  /  |  x  /

That’s it: the core rhythm of a line of iambic pentameter. But, within that line, a lot can happen.

Let’s start with the most obvious way to write a pentameter, to use a sequence of iambic words.⁵

x /  |  x / |  x   / |  x   / |x /
Above, below, without, within, around 

(Pope, The Temple of Fame: 458)

Lines like these are surprisingly hard to find! There aren’t that many ways of combining five words with the iambic stress pattern.

Luckily, you don’t have to make each foot consist of a single word. Alternatively, you can write a line in which each of the five feet is composed of two words, one unstressed and one stressed:⁶

  x /    |   x  /  |   x  /    |  x  /   |  x   /
The earth, the seas, the light, the days, the skies

(Traherne, The Salutation: 29)

Or you could mix and match:⁷

 x   / | x /  | x     /    | x    / |  x   /
But we,  alas!  are chased,  and you, my friends

(Marlowe, Edward II: 4.6.22)

As we saw with banana split earlier, words don’t have to line up with foot boundaries:⁸

  x    / | x    / |  x    /|x    /| x   /
That blondreth forth and peril casteth noon

‘Who blunders forth and imagines no danger’ 

(Chaucer, The Canterbury Tales G: 1414)

The words blóndreth, péril, and cásteth are not themselves iambs. In fact, they’re the exact opposite: they’re what are called trochees, sequences of syllables in the pattern stressed-unstressed.

But if you add an unstressed word before a sequence of trochees, they suddenly work in an iambic metre. They become staggered iambs.

As you can see, this gives you lots of possibilities. But if you had to follow this strictly, there would be many words you could never use in iambic pentameter, in particular anything with two stresses in a row: good grief!, or two unstressed syllables in a row: thoroughly.

What is a poet to do?

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This promotion is raising my stress levels

Throughout this article, I’ve been talking about stress in English as if it’s binary: either a syllable is stressed or it’s unstressed. But it’s actually more like a gradient between low stress and high stress.

To explain, I’d like to draw your attention to some funny facts about stress in English.

One funny thing is that two stressed syllables don’t like to sit next to each other: take the word sixtéen, which has its accent on the last syllable.

But when you put sixteen in the phrase síxteen cándles, the accent on sixteen recedes to the first syllable to avoid coming up against the stress at the start of cándles. In the resulting phrase, sixteen candles, the formerly stressed syllable -teen isn’t entirely unstressed — instead, it has a kind of half-stress, which we can write with a grave accent: síxtèen cándles. This phenomenon, by the way, is called stress shift.

Another funny thing: English words tend not to like long stretches of completely unaccented syllables. Long words tend to have a pattern of alternating stressed and unstressed syllables, although there’s always one clear primary stress.

For example, in the word álternàting, the first syllable al- has the primary stress, while the syllable -na- is stressed too, just less so. As we did with the results of stress shift, e can notate these secondary stresses with the grave accent, like so: cònnectívity, ìnteráctive, rètrogréssing. Note that, in the word connéct, the first syllable is totally unstressed, but when you add extra syllables to the end of the word, it’s pronounced with a slight stress of its own:

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It’s like there’s a force spacing out the stresses in English words roughly evenly, so that you don’t have stresses too close together or too far apart. This will come in handy shortly.

Another way this rough equal-spacing principle plays out in English is when you get a sequence of low-stress words in a row.

Low-stress words are things like articles (a, the), prepositions (of, by, with), and conjunctions (and, or). By default, these words don’t bear a strong stress of their own. Instead, they lean up against a more meaty, content word (like a noun, adjective, or verb), which gets a full stress. You can hear this effect in phrases like the dóg, by séa, and or élse.

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But, interestingly, when you get multiple low-stress words in a row, such as in tówn and ìn the cóuntry — in gets “promoted” a bit:

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All of these stress-related phenomena happen naturally in English speech. And they turn out to be poetically useful, because they help us create two variants of the basic iamb we’ve been working with up till now.

Take a look at this line, from Alexander Pope, marking out the stressed and unstressed syllables — by the way, this is called scanning a line — as we’ve been doing thus far:⁹

x   /  | x  /| x     / | x  x  | x /
To maids alone and children are reveal’d.

(Pope, Rape of the Lock 1.38)

As I’ve scanned it here, this line doesn’t work as an iambic pentameter, at least not according to the strict rules I’ve shown you so far: the fourth foot has no stressed syllable.

But this is actually not a problem. Listen to the natural way — or at least one natural way — this line is accented in spoken English:

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There’s a slight but noticeable difference in stress between the syllable -ren and the following syllable are. Are seems to get just a bit more stress than -ren. And this is enough for the metre to allow the foot -ren are to function like an iamb.

Let’s take another example:¹⁰

  /     / |x    / | x   / |x  /| x   /
Twixt crimson shame and anger ashie pale

(Shakespeare, Venus and Adonis 76)

Here, in the first foot, we have two stressed syllables, twixt and crim-.¹¹ But they’re not equally stressed, at least not in normal speech (if you can apply the word normal to any speech involving the word twixt).

There is another slight but noticeable difference between the stress level of twixt and crim-, with crim- taking a higher level of stress than twixt:

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And this difference is enough to allow two strong or stressed syllables to function as an iamb as well.

In other words, not every iamb has to consist of a completely unstressed syllable followed by a strongly stressed syllable. As long as the second of the two syllables is more stressed than the first, the result will still feel iambic.

To describe these phenomena, we can use the terms promotion, when an ordinarily unstressed syllable functions as a stressed syllable, and demotion, when the reverse happens. The result of promotion and demotion is the existence of variant feet, which we can call light iambs, where both syllables are unstressed (but the second syllable more so) and heavy iambs, where both syllables are stressed (but the second more so).¹²

We can notate these feet using the symbol we used for secondary stress: \

A light iamb, e.g. -ren are, will be notated as x \, for example:

x     /     |x /    |x     /   |x      \  | x  /
To   maids   alone   and   children   are   reveal’d.

(Pope, Rape of the Lock, 1.38)

And a heavy iamb will be notated as \ /, for example:

  \     / |x    /  |x   / |x  /| x   /
Twixt crimson shame and anger ashie pale

(Shakespeare, Venus and Adonis 76)

With these variations, the pentameter line starts to feel a lot more flexible and less monotonous. Compare the rhythms of these three lines, from different poets in different centuries:¹³

 x    /  | x  / |  x   / | x    /  |  x  /
You quite forget that we  must rouse to-day

(Chapman, The Gentleman Usher, I.i.25)

 \    / |x    \ | \   /| x   \ | \     /
Made courage, or made order, or made grace

(Pound, Canto LXXXI)

  \    /      | \     /      |  \       / | x   /| x   /
True thoughts, good thoughts, thoughts fit to treasure up

(Browning, Transcendentalism, 5)

So now you have seen the basic structure of the pentameter line in all its glory. But even with all the variations possible given the natural stress patterns of English, this pattern can still get monotonous, especially when you put hundreds or thousands of these lines in a row.

This is where some of the more radical variations come into play. And they’re not at all rare. In fact, it’s hard to analyse the meter of most poems without them.