In the month or so after Thom Gunn died in April 2004, I formed the habit at the end of the day’s work of taking down his Collected Poems and reading a poem. One night I noticed a small book beside the Collected Poems called Thom Gunn in Conversation with James Campbell. On page 19, I came on the following passage which made me sit up for a moment. When Campbell said: “Your new book, Boss Cupid, contains some new poems about your mother. Is this the first time you’ve written about her?” Gunn replied: “The second poem about my mother is called ‘The Gas Poker’. She killed herself, and my brother and I found the body, which was not her fault because she’d barred the doors, as you’ll see in the poem. Obviously this was quite a traumatic experience; it would be in anyone’s life. I wasn’t able to write about it till just a few years ago.”

I looked at those words again: “Obviously this was quite a traumatic experience; it would be in anyone’s life.” And then I burrowed among some books and found a quote from a letter which the American poet, Elizabeth Bishop, wrote to Anne Stevenson in 1964: “Although I think I have a prize ‘unhappy childhood’, almost good enough for the text-books – please don’t think I dote on it.” In that letter, Bishop wrote about her mother’s mental illness which began after Bishop’s father’s early death. “One always thinks that things might be better now, she might have been cured, etc ... Well – there we are. Times have changed.”

“Well, there we are.” I put the words beside Gunn’s: “Obviously this was quite a traumatic experience.” And I began to think about the connections between these two poets.

Both Bishop and Gunn in their work kept themselves distant from the reader. They described the world as though they watched it rather than fully took part in it; they did not explore themselves or their feelings in poems. Bishop wrote from a position of uneasy helplessness, a deep-seated fastidiousness and wonder at even the smallest object, and Gunn enjoyed having power and control over metre and rhythm and line.

Both were capable of immensely formal but oddly plain poetic diction; they often created elaborate formal structures in their poems. They wrote endings to poems which sometimes seemed to hover between conclusion and uncertainty, between what became known as closure and a sense that there was too much regret between the words for closure ever to be possible. Both Gunn and Bishop were also capable of elegant whimsy. They both also wrote strange, almost surreal poems about figures half-human, half-animal, or animals who had qualities entirely human, or humans who were secretly animals, poems such as Bishop’s “The Man-Moth” or Gunn’s “The Allegory of the Wolf Boy” or “Moly”.

They both were opposed to attitudes in poetry which seemed high-flown and untested by the detail of casual experience. For example, they both, without consulting each other, wrote parodies of Stephen Spender’s poem “I think continually of those who were truly great”. Gunn’s began:

“I think of all the toughs through history

And thank heaven that they lived, continually,

I praise the overdogs from Alexander

To those who would not play with Stephen Spender.”

In a letter to Randall Jarrell in February 1965, Bishop confessed that she had written a poem called “I practically never think of those who were truly great”, but added that she had never dared to print it.

Both Gunn and Bishop, having been brought up partly by aunts, partly in houses where they did not feel at home, left where they were from and settled in beautiful and exotic cities on the ocean with hills. Bishop moved from North America in 1952, at the age of 40, to Rio de Janeiro; and Gunn left England in 1954, at 24, and lived most of his life in San Francisco.

In many of the statements Gunn and Bishop made in their poems, there is a great reticence. Nonetheless, half-way through his career Gunn wrote explicitly about his homosexuality. When she died, Bishop left poems, and sometimes fragments of poems, which dramatised or dealt directly with her lesbianism. She did not publish these in her lifetime. Bishop said that she believed “in closets, closets and more closets”. While Bishop wrote only obliquely about her alcoholism in a poem such as “The Prodigal”, Gunn was more open about his interest in LSD and other drugs (he died of an overdose of heroin and speed). Both had great reservations about what was called “confessional poetry”, which became fashionable in the 1960s. The tendency is to overdo the morbidity. “You just wished they kept some of these things to themselves,” Bishop said. Gunn told James Campbell: “I don’t like dramatizing myself. I don’t want to be Sylvia Plath. The last person I want to be!”

In Bishop’s published correspon-dence the first reference to Gunn is in a letter to Robert Lowell in August 1968, when she was living in San Francisco: “Well, I’ve met some of the poets – and the only one I still really like is Thom Gunn.” In October that year she wrote to Marianne Moore: “One poet I’ve met here, almost a neighbour, I like very much, Thom Gunn. His poetry is usually very good, I think; he’s English but has lived here for a long time.”

Gunn remembered meeting Bishop for the first time in the spring of 1968: “I answered the phone one day and there was a very nice man I didn’t know … who asked me to come and have drinks with him and Elizabeth Bishop. Elizabeth had just moved to San Francisco. So I went over and … Elizabeth was drunk out of her mind. We made polite conversation all evening while Elizabeth occasionally grunted out a monosyllable. The next day [they] phoned and wondered if I would like to try again … and we got on wonderfully from then on ... Though I saw a lot of her, it wasn’t so that we spoke much about our private lives ... She and I talked about poets we liked and specific poems that we liked and disliked … I never let Elizabeth know this, but I didn’t particularly like her poetry myself at that time … There seemed to me something, for lack of a better word, that I’ll call ‘deeper’ in her that hadn’t gotten into the poetry. It wasn’t until Geography III … that I saw that side of her.”

In the TLS in 1990, Gunn set out to formulate further how Bishop’s last book of poems managed to change his view of her work. He described his early impression of her poetry as “coziness tinged with melancholy”, displaying “dazzling powers all the more remarkable for their limitation”. Then he wrote: “Her fifth book Geography III appeared in 1976, three years before her death, and here, all at once, everything was changed It was only 10 poems long, and yet its achievement was such that it retrospectively altered the emphasis and shape of an entire career.”

In one of the poems which Gunn admired, “Poem”, Bishop was given a small painting by a great uncle, of a landscape in Nova Scotia complete with water meadow, cows and geese, which she described carefully in the poem’s opening. This was the landscape of childhood; it was the place where she had last seen her mother, the place she was taken away from by her father’s family after her mother’s incarceration. To call it home would be to miss the point. The place she recognised in the painting was a place of loss.

Once she had recognised the precise place in the painting, what she called “this literal small backwater” which she had known as well as the painter, Bishop was faced with a problem about what to do next in the poem. Her vision, as she says, had coincided with that her grand-uncle the painter, but then she wondered in the poem if “vision” was the right word and concluded no, “vision is too serious a word”. Instead, it would be “our looks, two looks”. She was in search of more modest terms to describe a set of feelings which were dark and complex and must be rendered faithfully.

As she sought to end the poem, nothing would be said but everything suggested. The tone would be filled with helpless reverie, infinite and puzzled regret. Nothing would be stated too clearly, no names, no scenes recalled, no direct mention of how she might feel. Instead, in the poem, she looked at the painting again and remembered the scene: “Life and the memory of it cramped, / dim, on a piece of Bristol board, / dim, but how live, how touching in detail”.

And then a slow recognition that this was a place of loss, but that to name the loss would be to lose it further, to betray it somehow. Instead, she would revert to the melancholy to which Gunn referred, but this time with no possible coziness:

“ – the little that we get for free

the little of our earthly trust. Not much.

About the size of our abidance

along with theirs”

“Not much.” And then, once those two words, so calm, calculated, scrupulous and not to be contradicted, had been uttered, there was nothing more to be said, or almost nothing; it was essential, Bishop knew, to make no further comment. The emotion, somehow, was in the commas and the dashes, and in the spaces between the words, and in the silences, and in the sibilant at the end of the last word of poem, a word which seems to hang there, not to end, or not to end too easily:

the munching cows,

the iris, crisp and shivering, the water

still standing from spring freshets,

the yet to be dismantled elms, the geese.”

This poem of Bishop’s has interesting echoes of an early poem by Gunn, “In Santa Maria del Popolo”. Gunn’s poem was also about looking at a painting, in this case Caravaggio’s painting of the conversion of St Paul. Gunn, too, was interested in what lay in the painting and what lay outside the painting, but was almost part of it.

In this case, it was shadow: “I see how shadow in the painting brims / With a real shadow”.

The poem was not about the painting, but as in Bishop’s “Poem”, it was about the watcher; it was as much about what the eye does and how the self could be offered something – a glimpse of something else, a realisation of something much less certain than the image in the painting – as it was about what was actually seen in the painting.

As in the Bishop poem, the gazer in the Gunn poem was alone. As poets, both were in full command as they described the work which was in front of them, Bishop amused by the small marks her grand-uncle the painter had made, Gunn awed by the mystery of St Paul’s conversion, “the wide gesture of the lifting arms”, as painted by Caravaggio. Gunn’s rhyme scheme is ABABCDCD, the rhymes clear and masculine. It was in these years his customary mode. The voice was eloquent, impersonal, hushed. Gunn was interested in toughness, in violence, in what we might call advanced masculinity, and thus this scene in Rome, painted by someone who was later “strangled, as things went, / For money, by one such picked up off the streets” held his attention.

Thom Gunn was the least elegaic of poets, who described himself as ‘a cheerful person ... most of the time’. Photograph: Eamonn McCabe/The Guardian

In the poem, he turned, “hardly enlightened” from the scene. Maybe that was enough, just to leave it at that. In turning, however, he allowed the watcher a sudden recognition of something as he noticed, in the last stanza, people praying in the church: “Mostly old women: each head closeted / In tiny fists holds comfort as it can.”

Suddenly, he was writing about the powerless, the weak, the supplicant. The eye, which had been contemplating power and grandeur now became tender. He had been somehow shocked into pity by turning from the shadows and the mysterious image on the road to Damascus towards the powerless world, much as Bishop had come closer than she ever had before, or would again, to making clear what the landscape of childhood had meant to her. Gunn wrote: “Their poor arms are too tired for more than this”.

We wait then for the final word which must rhyme with “this”. Thomas Wyatt rhymed the word “this” with “kiss”; Shakespeare in the sonnests rhymed “this” with “amiss” and “is”; Ben Jonson rhymed “this” with both “is” and “kiss”; Yeats rhymed, or half-rhymed, “this” with “ice”; each of these rhymes offered a sense of certainty and finality. Now, however, Gunn was aware, as Bishop had been in her poem too, that his ending must be tentative, strange and open; it could not be a single conclusive word.

In the meantime, he needed a rhyme for “can” in the fourth last line and this could easily be found as “man” in the second last line. So the end of the poem could read thus:

Their poor arms are too tired for more than this

– For the large gesture of solitary man

And now Gunn needed his final line, where he wanted the rhyme with “this” to have a weak sound to emphasise that the poem was ending, as Bishop’s had, with a kind of sigh rather than a ring of certainty. He wrote: “Resisting, by embracing, nothingness.”

I read “nothingness” here partly, or as much as I can, as a simple word, the abstract noun from “nothing” almost restored to the language of poetry from its tedious time in philosophy. Nothingness. Its dying fall, the emphasis on the first syllable and the last two dying away in a sibilant, made it close in sound (but not, of course, in sense) to Bishop’s comma and last two words in her last line of “Poem”: “the yet-to-be-dismantled elms” and then a comma (which silently contained an emphatic “and”), and then the final two words, “the geese”, which suggested that the observers, so powerful and in control at the beginning of both poems, have been oddly weakened or made sad and aware by something only half understood.

In September 1977, when she was on the island of North Haven off the coast of Maine, Bishop learned that her friend Lowell had died. The following year she set about writing an elegy for him. She had previously tried and failed to write an elegy for her mother, and for her lover, Lota de Macedo Soares, who had killed herself in New York in 1967. The poem for Lowell, called “North Haven”, was one of her last poems. Its gravity emerges softly. When you read the line, “The goldfinches are back, or others like them”, it is easy not to spot the grim suggestion that the precise goldfinches are in fact not back at all – they are dead. And thus Bishop has perhaps only slightly prepared the reader’s unconscious for what is coming when the white-throated sparrow’s “five note song”, which might seem innocent, is, in fact, “pleading and pleading”, and “brings tears to the eyes”.

Then she had to work out what word to use as an end-rhyme, a word that will rhyme with “eyes”, since the third and fifth line of each five-line stanza of “North Haven” ends on a rhyme. In the sonnets, Shakespeare rhymed “eyes” with “lies”, “cries”, “arise”, “devise” and “despise”. George Herbert also rhymed it with “rise” and “suffice”.

In the next line, Bishop came as close as she could to stating something that was true; the “coziness tinged with melancholy” has gone and it has been replaced by another sort of melancholy, a slow, stoical melancholy, when she says: “Nature repeats herself, or almost does.”

What the following line does now is oddly miraculous, a slow, incantatory dramatisation of the tentative and withholding nature of Bishop’s process as a poet. The last line of this stanza has six words, each in an iambic beat; there is a caesura after three, marked by a semi-colon. The words are in italics, which suggest not emphasis as much as a voice whispering. The last three words, each ending with a sibilant and half-containing the word “sigh”. And what the voice says now is as much as she can say. It is filled with ambiguity and restraint:

Repeat, repeat, repeat; revise, revise, revise.

In the meantime, in San Francisco, Gunn did not publish a book of poems between 1982 and 1992, when he published The Man with Night Sweats. In the 17 poems about friends who died of Aids, which make up Part IV of this volume, Gunn, the least elegiac of poets, someone who described himself as “a cheerful and rather superficial person most of the time” (just as Bishop wanted “Awful but Cheerful”, a phrase from one of her poems, etched on her tombstone) produced the greatest elegies of his age. He used everything he knew, at times exploiting an impersonal, heavily metred and sharply rhymed tone in which all the obvious or easy terms of feeling had been excluded.

When I met Gunn first in San Francisco in the early 1990s, he seemed amused, almost pleased, at how little known he was, compared to Allen Ginsberg in America or Ted Hughes and Philip Larkin in England. Bishop’s fame too, during her lifetime, seemed pale compared to contemporaries such as Lowell and John Berryman. What is interesting now is how, by virtue of their poems, both Bishop and Gunn have moved from the shadow into the light. Their insistence on finding a tone which almost explored and then almost disguised their experiences, and their great, astringent withholding, seem finally to have worked wonders for the readers of their poems in these years after their deaths.

• Colm Tóibín’s On Elizabeth Bishop is published by Princeton.