In his astonishingly frank Sonnet 133 William Shakespeare attempts to come to terms with the fact that his young lover is also having an affair with his mistress.

The sonnet in one fell swoop answers two principal questions: first, what 'black deeds' of his Dark Lady's he may be referring to in the closing couplet of Sonnet 131, and second, who the woman might be that appears in the crisis which besets his relationship with the young man between Sonnets 33 and 42.

And while there is of course no external, cast-iron proof that these sonnets do constellate to form a coherent picture, Sonnet 133 is in fact only the first of several sonnets to strongly suggest they do.

What it leaves no doubt about, and what subsequent sonnets will make even more explicitly clear, is that William Shakespeare is for the second time in the collection talking about a relationship that has turned triangular.

With Sonnet 132, William Shakespeare suspends the charge brought against his mistress at the end of the previous sonnet that she is 'black' in nothing so much as in her deeds, and instead pleads with her to have pity on him as he suffers under her disdain for him. At first glance and in isolation it might seem, then, that such 'black' deeds as were mentioned in the closing couplet of Sonnet 131 are nothing but this attitude of hers towards him, but as we saw then and also discuss here, this is unlikely to be the case since a 'ladylike' level of decorum requires a woman at the time to be quite unapproachable and at least apparently aloof, and Sonnet 133 will confirm in no uncertain terms that the deeds in question are of a different nature altogether.
The sonnet thus stands in a long tradition of poetry that has a male lover pine for his unattainable and/or contemptuous mistress, and while on the surface it appears to express itself in positively chaste tones – certainly when compared to the exceptionally explicit Sonnet 129 – it still carries some subtle but nonetheless perfectly evident sexual undertones which it combines, so we get the impression, with just a tinge of irony.

Sonnet 131 connects directly to Sonnet 130 and now invokes a further poetic trope, that of the tyrannous mistress who makes her admirer to groan for love, even though this woman is – as Sonnet 130 made clear – categorically different to those other beauties traditionally so characterised and, as this poem also is fairly quick to point out, her beauty is not universally considered to have the capacity to make a man thus suffer an aching desire for her.

​Shakespeare then once again plays on his awareness of this circumstance and again acknowledges, indeed asserts, that as far as he is concerned she fully has that power so ascribed to other ladies with their light-skinned, fair-haired beauty, and that her darker skin and black hair to him constitute the most beautiful thing there is, only to then in the closing couplet ambush her with a surprising twist: it is not, he startlingly declares, your outward appearance that is black, as in 'ugly,' it is your deeds that make you so, and that, as far as I can tell, is where you get your bad reputation from.