Hay Festival 2012: Mario Vargas Llosa on Roger Casement Seen from the leafy meadow that surrounds it, the castle, with its cubic shape, robust black stones, turrets, great windows, chimneys, shields and its cathedral-like facade, is imposing. Inside, it is a ruin, and falling to pieces. Christopher and his family, who have taken refuge in a few rooms on the ground floor, hope that in the course of one of those daily crumblings the thick walls will spit out the sacks of gold that, according to the lore of Ballymena, the diabolical reverend Colville buried within them before his death. Galgorm Castle has been in Christopher's family, the Youngs, since the mid-nineteenth century, and one of the current owner's most illustrious ancestors was Rose Maud Young, who, despite coming from a staunchly Unionist family - protestant and pro-British - was one of a handful of Antrim ladies who had a very active part, towards the end of the nineteenth century, in the renaissance of Gaelic language and culture, an endeavour that brought them closer to their traditional adversary, Irish nationalism. In addition to writing a detailed diary, Rose Young published three volumes of poetry, legends and songs in Gaelic which had been preserved orally and which she collected herself among fishermen and peasants in the old hamlets of Antrim. As well as being beautiful, cultured and liberal, Rose Maud Young - whose gatherings united Presbyterians, Anglicans and Catholics - was a friend and protector of Roger Casement (1864- 1916), the fascinating character in whose footsteps I have ventured to follow throughout these parts of Ireland. As an adolescent, at the end of the nineteenth century, Casement studied at Ballymena Academy for three years, and spent many weekends at Galgorm Castle, as recorded in Rose Maud Young's scrupulous diaries. It was here, perhaps, that he read the memoirs of great English explorers such as Livingstone and Stanley, who gave him an appetite for travel, and for Africa. Although he was born in Sandycove, Dublin (very near Martello Tower, where Joyce's Ulysses begins), his family came from here and he spent a large part of his childhood and adolescence in Antrim. As an adult he returned to this land as often as he could, to cure his nostalgia and calm his spirit after the great torments that visited him in the course of a life as intense, as adventurous and as full of risk as that of a knight in an epic novel. He devoted a large part of that to denouncing the exploitation of indigenous communities in Africa and in the Amazon, and similarly - especially in his later years - to fighting for Irish independence. When, on the eve of his execution, the impeccable hangman of Pentonville prison, Mr John Ellis (who was a barber in his spare time), embarked on the macabre ceremony of weighing him and measuring him in order to ensure that the rope with which he was to strangle him had the requisite consistency and height, Roger Casement asked that his remains be buried not far from here, in Murlogh Bay, to which he referred in his letters as "Paradise Bay." The British authorities denied him his wish: they buried him in the prison where they hanged him (for treason, since he had conspired with the Germans during the First World War to smuggle arms to the Irish revolutionaries of the Easter Rising of 1916), in an unmarked grave and next to a famous butcher of women, Dr Crippen, executed some years earlier. It was not until 1965 that his remains were returned to Ireland. They have now been laid to rest in the Dublin cemetery of Glasnevin, beneath a sombre tombstone inscribed in Gaelic (a language that, despite his best efforts, he never learned): "He died for Ireland." Roger Casement had good reason to want to be buried in Murlogh Bay: it is the most beautiful place in Ireland, Europe, and possibly the world. It is the culmination of one of the loveliest glens in Antrim, those valleys or gorges that, between mountains of every shade of green, streams, waterfalls and sheer cliffs, descend to meet a raging sea that crashes against sculptural rocks. Hordes of birds swoop through the sky and when the days are as bright and cloudless as those the Celtic gods have granted me, you can make out, very close by, the mass of Rathlin Island, in whose villages Rose Maud Young gathered many of the poems and stories of ancient Ireland. The landscape seems to be uninhabited by humans, nature in its purest, most virginal, most edenic state. It's just a mirage, of course. This land of castles, glens, ghosts, poets and famous wandering storytellers (the seanchaí) has also been one of the most violent in Europe, where ethnic and religious wars have sown blood, hatred and resentment everywhere. A trace of all this remains in the hills around Murlogh Bay, where, some years ago, Sinn Féin erected a monument to Roger Casement. Not long afterwards it was blown up by an Ulster terrorist group and has not been rebuilt since. What will happen now in Northern Ireland? Almost everyone I spoke to was optimistic, and believed that the future would reinforce the process that began with disarmament, and that politics would definitively replace fratricidal war. One of those optimists is Christopher Brooke. Let us hope that Cuchulain and the other heroes of the Irish pantheon are listening. We say goodbye beneath the portrait of the shadowy Doctor Colville. His gaze is beatific and gently mocking. His pale and narrow little eyes seem sorry to see us go. Because in this country even ghosts and pact-prone theologians valiantly practice the vice of hospitality. To buy The Dream of the Celt (Faber, £18.99) at a discounted price, go to books.telegraph.co.uk