Darley was the eldest child of Arthur Darley, of the Scalp, County Wicklow. The poet, however, was not born there, but in Dublin, in the year 1795. While he was a child, his parents emigrated to the United States; and the boy spent the first ten years of his life at the family home in Wicklow. In due time, and subsequent to the return of his parents from America, he went through the usual scholastic routine, though he did not graduate at Trinity College, Dublin, till his twenty-fifth year--a delay in great part due to what, then and later, he considered a disastrous impediment of speech. From the loss of a scholarship to the social deprivations he underwent in London, this infirmity, he declared, was his evil fortune. His first book, _The Errors of Ecstasie_, was published (1822) in London, where he had settled. Needless to say, as this volume consists mainly of a dialogue between a Mystic and the Moon, the reading public remained in absolute ignorance of the new poet. His second book (1826) consisted of a series of prose tales and verses, collectively entitled--_The Labours of Idleness; or, Seven Nights’ Entertainments_--set forth as by “Guy Penseval.” Three years later appeared his chief work, _Sylvia_. Notwithstanding its divers shortcomings, some of them frankly acknowledged by the author himself, _Sylvia_ is a creation of genuine imagination, and possesses a haunting and quite distinctive charm. Both the merits and demerits of his too often uncontrolled style are adequately indicated in the criticism of Mr Ingram: “[frequently] his wild Celtic fancy breaks its curb and carries him into clouds of metaphor as marvellous as they are musical, although often the flight ends by a hasty and undignified descent to commonplace earth.” There is no commonplace, however, in his exquisite faëry verse, which, in the words of the same critic, “is among the loveliest in the language; at times is even sweeter than Drayton’s, and is as fantastic as Shakespeare’s own.”
For ten years the poet kept silence; but in 1839 he issued his fragmentary and extraordinary _Nepenthe_--a poem which, with all its brilliant quality and daring richness of imagery, might well be taken as an example of the Celtic genius _in extremis_--so unreservedly does he give way to an uncontrolled imagination. Perhaps the best thing said about _Nepenthe_ is in a letter from the author himself, wherein he writes:--“Does it not speak a heat of brain mentally Bacchic?”