"Who breaks a butterfly upon a wheel?" is a quotation from Alexander Pope's "Epistle to Dr Arbuthnot" of January 1735.

It alludes to "breaking on the wheel", a form of torture in which victims had their long bones broken by an iron bar while tied to a Catherine wheel.^[1] The quotation is used to suggest someone is "[employing] superabundant effort in the accomplishment of a small matter".^[2]

The quotation is sometimes misquoted with "on" in place of "upon".

The line "Who breaks a butterfly upon a wheel?" forms line 308 of the "Epistle to Dr Arbuthnot" in which Alexander Pope responded to his physician's word of caution about making satirical attacks on powerful people by sending him a selection of such attacks. It appears in a section on the courtier John Hervey, 2nd Baron Hervey, who was close to Queen Caroline and was one of Pope's bitterest enemies. The section opens as follows:^[3]

Let Sporus tremble –"What? that thing of silk,
Sporus, that mere white curd of ass's milk?
Satire or sense, alas! can Sporus feel?
Who breaks a butterfly upon a wheel?
Yet let me flap this bug with gilded wings,
This painted child of dirt that stinks and stings;
Whose buzz the witty and the fair annoys,
Yet wit ne'er tastes, and beauty ne'er enjoys,

"Sporus", a male slave favoured by Emperor Nero,^[3] was, according to Suetonius, castrated by the emperor, and subsequently married.^[4] Pope here refers to accusations made in Pulteney's Proper reply to a late scurrilous libel of 1731 which led to Hervey challenging Pulteney to a duel. Hervey's decade-long clandestine affair with Stephen Fox would eventually contribute to his downfall.^[5][6] As first published the verse referred to Paris, but was changed to Sporus when republished a few months later.^[7]

"What? that thing of silk" uses a metaphor of a silkworm spinning that Pope had already used in The Dunciad to refer to bad poets. "Ass's milk" was at that time a common tonic, and was part of a diet adopted by Hervey. "This painted child" comments on make-up such as rouge used by the handsome Hervey.^[3]

Another graphic instance of the usage can be found in An Introduction to Harmony by William Shield (1800), wherein he writes: "Having brought this Introduction to Harmony before that awful Tribunal, the Public, without first submitting it to the inspection of a judicious friend, I shall doubtless merit severe correction from the Critic; but as my attempt has been rather to write a useful Book, than a learned Work, I trust that he will not break a Butterfly upon the wheel for not being able to soar with the wings of an Eagle."^[8]

William Rees-Mogg, as editor of The Times newspaper, used the "on a wheel" version of the quotation as the heading (set in capital letters) for an editorial on 1 July 1967 about the "Redlands" court case, which had resulted in prison sentences for Rolling Stones members Keith Richards and Mick Jagger.^[9]

The philosopher Mary Midgley used a variation on the phrase in an article in the journal Philosophy written to counter a review praising The Selfish Gene by Richard Dawkins, where she said that she had "not attended to Dawkins, thinking it unnecessary to break a butterfly upon a wheel."^[10]

British rock band The Mission released a single entitled "Butterfly on a Wheel" in 1990,^[11] and "Break a Butterfly on a Wheel" is the penultimate track on Similarities, a compilation album by Scottish rock trio Biffy Clyro.^[12] The phrase has been used in the lyrics of songs including "Soul Asylum" by The Cult (from the 1989 album Sonic Temple),^[13] "Paradise" by Coldplay,^[14] and "Falling Down" by Oasis.^[15]

A film titled Butterfly on a Wheel was released in 2007.^[16]