One day during the summer I was driving along a road near my home in Gwynedd when I saw a solitary figure standing immobile at the roadside, looking into a wood. It was not an impenetrable, forest-like wood, but one of those thickets of Welsh oak through whose foliage the light is always playing, birds flit in and out and there is green hillside beyond.

One day during the summer I was driving along a road near my home in Gwynedd when I saw a solitary figure standing immobile at the roadside, looking into a wood. It was not an impenetrable, forest-like wood, but one of those thickets of Welsh oak through whose foliage the light is always playing, birds flit in and out and there is green hillside beyond.

The man suggested to me an Easter Island statue, craggy and enigmatic, but I knew him to be RS Thomas, the great Welsh poet who died on Monday. For half a century his had been a grand, brooding presence in our part of the country, for ever, it seemed, looking into the woods of Wales and trying to divine their messages. He was an Anglican parish clergyman, but he was also a man of the earth who believed God to be Nature itself.

This is one of the oldest Welsh poetic traditions. The 14th-century lyricist Dafydd ap Gwilym likened another Welsh wood to a cathedral, where it was the nightingale that raised the Host to the sky. Ravens and seagulls, foxes and horses, all swarmed across the landscapes of Welsh poesy, and they were the emblems of a people's profound affinity with the land they inhabited - a people remote from the affairs of the greater world, but close to their neighbours, the birds and beasts.

Most nations have their nature poets, who see Heaven in a wild flower, but in Wales this preoccupation with the animal kingdom has had to it a kind of poignancy, because so often it has been the reflection - sometimes the instrument - of national impotence. It has not been a sign of reconciliation, but of resentment. Only the wild creatures, it seems to say, are on our side in our endless struggle to be ourselves; only the swallow can be trusted to carry our messages, or the owl to advise us justly. The birds and the animals became, in their allusive way, images of nationalism.

I myself, patriotic Welsh extremist though I am, hate the word "nationalism". It speaks to me of narrowness, envy and xenophobia. RS Thomas, though, frankly called himself a nationalist. Not for him the definition of true patriotism offered by another Welsh writer, the Catholic playwright Saunders Lewis - one of the founders of Plaid Cymru - as "a generous spirit of love for civilization and tradition and the best things of mankind". Thomas certainly loved the best things of mankind, but there was a more atavistic streak to his sort of patriotism. Like so many of his people down the centuries, he was plagued by one particular secular passion: his detestation of all that the English had done to the Welsh. So much that was good about Wales, he thought, had been corroded by Anglicisation, and so much that was vulgar substituted.

A plague it was, and still is for many another kind and godly Welshman. I suppose the same ache of the heart troubles many Arabs when they feel they must dislike Jews on principle, or, for that matter, troubled many a decent young Englishman when he machine-gunned an unknown German into oblivion. Welsh people are not as a rule xenophobic, and RS Thomas certainly wasn't, but the condition of a minority nation has ingrained in many of them a generic resentment of their one particular bête noire: the Saxon, the Englishman.

Especially in a poet and a man of God, this nagging, intuitive aversion, soured over the generations into disillusionment - for there seems no gentle way of stopping the Anglicisation of Wales - must strain the conscience. It is a noble cause, to preserve an ancient way of life, an ancient tongue, a beloved identity, but set against the preoccupations of a planet, it is a petty cause, too. While we argue about the preservation of the language, or the tax-raising powers of our Assembly, whole continents are rising to power out there, millions are being born, and mankind is reaching toward inconceivable new objectives. There are 2.75 million people in Wales. There are six billion members of the human race!

So we tend to turn in remorse, as perhaps this grand old poet did, back to the elementals: the woods, the hills, the skylarks, the drifting sound of an old language, what Thomas once called, in a moment of despondency, the bones of a dead culture. He was active in the patriotic cause almost until the day he died, and there are some who say, as they have said of Wales, that as an artist he would have done better to abandon it.

I don't agree. RS Thomas did not write his poetry in Welsh, but there has never been a poet more profoundly Welsh. This has always been an uneasy country, tormented by conflicts, and his work is the greater for the sad tension that informs it - the sense of yearning for some grander condition that has been sentimentalised in Wales as hiraeth. He seemed to me in his last years to have become a happier man. Perhaps he thought that Wales really was achieving serenity at last, or perhaps he had come to see it more clearly as only an infinitesimal chip in some divine design.

Whatever it was, when I recall him at the roadside there, looking silently into the trees, the memory gives me a sense of calm and liberation, as Wales itself does, when it is happy.

The writer's 'Our First Leader: a Welsh fable' is published next month by Gomer