Of all the poems in the collection first published in 1609, Sonnet 107 most clearly and most compellingly seems to refer to external events that shape Shakespeare's world.

Because of this, it takes up a pivotal position in the canon, since it may therein hold clues to both its date of composition and to the person it is addressed to. And while there is little doubt in most people's mind that its references are indeed intentional and allude to some momentous occasion that has passed off signally better than anyone at the time would have predicted, and that in the ensuing calm and peace our poet feels that his love and his poetry have been given a new lease of life, no-one can tell with absolute certainty just what Shakespeare is actually referring to or whom he is talking to, or even whether the two factors are directly or only indirectly linked, or not at all.

There are, however, significant clues, and so much of our discussion of this sonnet will concern itself with what these are and what they mean for our reading of this and the other sonnets in the series.

Sonnet 106 sees Shakespeare return to eulogising his young lover in outwardly straightforward terms. And rather than looking ahead to times to come when his poetry will continue to pay tribute to his love long after both he and his lover have gone, as several of the other sonnets have done, he here casts his eye back to the past through the lens of the poets who have talked about the people of their day, and comes to the conclusion that they were doing just as he is doing now: trying to express the epitome of beauty. But since this had not yet been reached, because the young man of his love had not yet been born, they ended up not so much chronicling their age as predicting an age to come with his appearance in this world; and yet of course now that he is here, it is possible for Shakespeare and anyone who shares the privilege of being in his presence to admire him, but Shakespeare and his contemporaries still find it impossible to do him justice with their words.

Sonnet 105 presents a playful paradox that is no doubt fully intended on William Shakespeare's part.

Addressing, for a change, not his young lover directly, but speaking to the world in general about him and about his love for him, he tells us that we should not see, and in seeing so by implication judge, this love as the worship of a human and therefore by necessity false god, and then proceeds to deify this same object of his love in terms that – in a culture of immensely powerful religious strictures – comes scandalously close to sacrilege by effectively calling him 'the one and only' and investing him with qualities that prompt immediate comparisons to the holy Trinity.

With his celebrated and much-debated Sonnet 104, William Shakespeare appears to set out to do primarily three things: first and foremost, to reassure his young lover that even now, after some appreciable time has passed since they first met, he, the young lover, is still as beautiful to him, our poet, as he was on the very first day; in other words that for him, Shakespeare, the fact that his young lover may be showing signs not so much perhaps of age as of having grown up, doesn't matter.

Secondly, to alert the reader and listener – most particularly the reader and listener of the future – to our mortality and to the passing of time and to the fading nature of youth and beauty, even if the changes inflicted by time are not perceptible in the moment.

And thirdly – as it turns out for some people today still most controversially – to offer a time frame for the relationship with his young man of precisely and specifically three years. All of which, and particularly of course the latter, we will discuss in this episode.

Sonnet 103 is the fourth and last in this group of four sonnets with which William Shakespeare seeks to excuse himself for not writing more poetry to, for, or about his young lover lately.

Like the first two in the group, Sonnets 100 & 101 – which are so closely linked that we may treat them as a pair – this sonnet also references the poet's Muse, but unlike these two it does not address itself to the Muse, but speaks about her, or rather the paucity of the output she facilitates the production of in view of the abundant wealth of qualities possessed by the the object of which she is supposed to help the poet speak, namely, the young man.

With Sonnet 102, William Shakespeare returns to addressing his young lover directly, though still in explanation and indeed defence of the extended period of silence of which Sonnets 100 & 101 spoke, both of which were addressed to his own Muse, admonishing her for her absence.

In contrast to those two poems, Sonnet 102 takes full responsibility for the dearth of praises sung in sonnet form to the young man and sets out its reasoning in an argument that is so elaborate, it doesn't quite fit the form: Shakespeare never actually manages to finish his sentence that covers the entirety of the second and third quatrain, which gives the poem an almost improvised quality that may or may not be fully intended.

Although at first glance Sonnet 101 can stand on its own, it so closely connects to Sonnet 100 that it really in all likelihood should be considered to form with it a pair within this group of four sonnets that they are both part of.

Like Sonnet 100, it addresses itself to Shakespeare's Muse – his poetic inspiration – in a series of rhetorical questions that seek to encourage her to return to him to write further poetry for and about his young lover.

In doing so, it purports to offer a possible explanation for the Muse's absence, but immediately rejects this as unsatisfactory, reminding the Muse of her duty to give the object of his love longevity way beyond his own presence on earth.

Sonnet 100 is the first in a group of four sonnets that speak of a hiatus in Shakespeare's poetry writing to his young lover.

In the collection first published in 1609, this follows Sonnets 97 and 98, which both highlight an absence from the young man that has felt to Shakespeare like winter, with Sonnet 99 acting as something of a bridge between the two themes. Whether, therefore, the silence on Shakespeare's part coincides with this absence, we cannot say with certainty, but it would appear plausible to say the least...