‘Theirs not to reason why, / Theirs but to do and die’: these lines have become famous, although they’re often misquoted. The quotation originated in the 1854 poem ‘The Charge of the Light Brigade’ written by the UK Poet Laureate of the time, Alfred, Lord Tennyson (1809-92). Tennyson, who was Poet Laureate for a record 42 years, wrote the poem in response to a very specific event, and it was this event that inspired the lines, ‘Theirs not to reason why, / Theirs but to do and die’. Let’s take a look at the poem, and the event.
The poem is one of the rare instances of a Poet Laureate producing a good poem while in office, a poem that would last beyond the occasion for which it was written. And although ‘The Charge of the Light Brigade’ was, in one respect, an occasional poem, it also offered a timeless reflection on the senselessness that accompanies much of war, while also praising the unflinching bravery and sense of duty of the soldiers who gave their lives. And the famous ‘theirs but to do and die’ line in the poem encapsulates this message.
The poem was inspired by one of the greatest calamities in British military history: on October 25, 1854, during the Crimean War, the British Light Cavalry Brigade, comprising some 670 men, charged disastrously against some 25,000 Russian soldiers. Lord Raglan’s plan was to send the Light Brigade to prevent the Russians from removing some guns 
that had been seized from Turkish positions. But somehow – and precisely what happened has never become exactly clear – and somewhere along the chain of command there was a ‘blunder’, and the Light Brigade was instead sent on a frontal assault against a vastly superior army, rather than on the gun-capturing mission. The Light Brigade charged, as commanded, but were quickly forced into a retreat.
Tennyson wrote the poem on 2 December 1854 in response to an article he read about the charge in The Times newspaper, and the poem was published in The Examiner a week later, on 9 December 1854, while public shock at such a waste of life was still high.
As many schoolchildren know, the poem condemns the charge (and resultant heavy casualties suffered by the Light Brigade) as a terrible ‘blunder’. But Tennyson also praises the bravery and nobility of the soldiers, the ‘Noble six hundred’, who obeyed their orders to charge and went to their deaths. (The original report had the number at nearer 600 men, although it later emerged that the exact number was nearer 700; but ‘Noble seven hundred’ wouldn’t have scanned, and Tennyson, whilst annoyed with himself for the inaccuracy, reluctantly let the initial number stand as a record of the public feeling that attended news of the disaster.) An estimated 278 soldiers were killed or wounded in the charge.
The famous line of the poem, ‘Theirs but to do and die’, appears in the second stanza:
‘Forward, the Light Brigade!’
Was there a man dismayed?
Not though the soldier knew
Someone had blundered.
Theirs not to make reply,
Theirs not to reason why,
Theirs but to do and die.
Into the valley of Death
Rode the six hundred.
‘Theirs but to do and die’, note: the line is often misquoted as ‘Theirs but to do or die’, which gives the poem a different inflection. But Tennyson’s point is that there is no question of whether the soldiers will or will not carry out their military duty, even when presented with such a wrongheaded command to charge, and even when following the command may lead them to their deaths (as would sadly be the case for so many of the men).
No, they will do it and die, for queen and country. Soldiers are trained not to question the reasons behind a command, but to obey that command when given:
Theirs not to reason why,
Theirs but to do and die
This does two things: it reinforces the idea that the soldiers were doing exactly what they are trained to do, and so they are free from blame; but through doing so, it reminds us squarely where the blame does belong, which is with those who gave the command. ‘Theirs but to do and die’ is good advice when it comes to a necessary order to fight to the death, but to command men to give their lives for something unnecessarily is unforgivable.
After the charge, not much remains of the ‘six hundred’ who rode into battle – nearly half of them had sustained heavy injuries or been killed, while the other half felt that the whole charge had been a colossal waste of life. Tennyson’s use of the word ‘left’ (‘All that was left of them, / Left of six hundred’) picks up on the word’s use earlier in the same stanza (‘Cannon to left of them’), but shifts the word’s meaning from a spatial sense to one denoting the sacrifice the men have made. As the old line attributed to Bertrand Russell has it, war doesn’t determine who is right – only who is left.
Tennyson wrote better couplets than ‘Theirs not to reason why, / Theirs but to do and die’, and better poems than ‘The Charge of the Light Brigade’. But perhaps there is no more famous poem written about a specific military occasion, whose insistent dactylic metre (heard so well in the poem’s opening lines, ‘Half a league, Half a league, / Half a league onward’) captures both the plaintive nature of the catastrophe and the dogged and dutiful charge of the men into ‘the valley of death’.