What is Pyrrhic Substitution in Poetry?

So, a pyrrhic substitution is made when a foot of poetry has these two unaccented beats despite the fact that the rest of the line dictates that it should be otherwise. It is used when a syllable that should be stressed according to the iambic or trochaic meter does not need or want that emphasis.

An example would be this line from Wilfred Owen’s ‘Anthem for Doomed Youth’:

“Not in the hands of boys, but in their eyes.”

Now, when read aloud, it would sound something like this:

NOT in / the HANDS / of BOYS / but in / their EYES

The keen-eyed will notice that the first foot is a trochaic substitution, meaning that the ‘de dum’ rhythm has been replaced by a ‘dum de’, to emphasise the ‘NOT’. But the pyrrhic substitute can be found in the fourth foot.

Now, these syllables both need to be unstressed, because ‘but IN their EYES’ would not sound quite right and, more importantly, the emphasis of the word is completely unnecessary.

Similarly, if Owen had plumped for a trochee and had “BOYS BUT in their…” the result is actually quite ugly. So, because it is neither desirable nor necessary to have these syllables stressed, they are the unstressed beats of the pyrrhic meter.

Another good example of pyrrhic substitution can be found in the fifth line of Shakespeare ‘Sonnet One’.

“But thou contracted to thine own bright eyes”

But THOU / con TRACT / ed to / thine OWN / bright EYES

Again, there is no sense in stressing the ‘TO’, so this foot consists of two unaccented beats.

In Shakespeare’s case, ‘OWN’ which is the next stressed syllable has the additional emphasis to it.

It’s worth remembering that pyrrhic substitution is not simply used when the stress of a particular syllable seems ugly (although that’s a great way to identify a pyrrhic foot). It serves a larger purpose within the line and the poem as a whole.