As early as 1628, that is, in his tenth year, he composed his Tragicall History of Piramus and Thisbe, an epic romance written in a six-line stanza, a style of his own invention. It is not too much to say that this work is the most astonishing feat of imaginative precocity on record; it is marked by no great faults of immaturity, and possesses constructive merits of a very high order. Two years later the child wrote another and still more ambitious poem, Constantia and Philetus, being sent about the same time to Westminster School. Here he displayed extraordinary mental precocity and versatility, and wrote in his thirteenth year the Elegy on the Death of Dudley, Lord Carlton. These three poems of considerable size, and some smaller ones, were collected in 1633, and published in a volume entitled Poetical Blossoms, dedicated to Lambert Osbaldeston, the head master of the school, and prefaced by many laudatory verses by schoolfellows.
In 1637 Cowley was elected into Trinity College, Cambridge, where he betook himself with enthusiasm to the study of all kinds of learning, and early distinguished himself as a ripe scholar. Portraits of Cowley, attributed to william Faithorne and Stephen Slaughter, are in Trinity College's collection. It was about this time that he composed his scriptural epic on the history of King David, one book of which still exists in the Latin original, the rest being superseded in favour of an English version in four books, called the Davideis, which were published after his death. The epic deals with the adventures of King David from his boyhood to the smiting of Amalek by Saul, where it abruptly closes.
In 1638 Love's Riddle and a Latin comedy, the Naufragium Joculare, were printed, and in 1641 the passage of Prince Charles through Cambridge gave occasion to the production of another dramatic work, The Guardian, which was acted before the royal visitor with much success. During the civil war this play was privately performed at Dublin, but it was not printed till 1650. It is bright and amusing, in the style Common to the "sons" of Ben Jonson, the university wits who wrote more for the closet than the public stage.
The learned quiet of the young poet's life was broken up by the Civil War; he warmly espoused the royalist side. He became a fellow of Trinity College, Cambridge, but was ejected by the Parliamentarians in 1643. He made his way to Oxford, where he enjoyed the friendship of Lord Falkland, and was tossed, in the tumult of affairs, into the personal confidence of the royal family itself.
In 1647 a collection of his love verses, entitled The Mistress, was published, and in the next year a volume of wretched satires, The Four Ages of England, was brought out under his name, with the composition of which he had nothing to do. In spite of the troubles of the times, so fatal to poetic fame, his reputation steadily increased, and when, on his return to England in 1656, he published a volume of his collected poetical works, he found himself without a rival in public esteem. This volume included the later works already mentioned, the Pindarique Odes, the Davideis, the Mistress and some Miscellanies. Among the latter are to be found Cowley's most vital pieces. This section of his works opens with the famous aspiration:
Cowley obtained permission to retire into the country; and through his friend, Lord St Albans, he obtained a property near Chertsey, where, devoting himself to botany and books, he lived in comparative solitude until his death. He took a practical interest in experimental science, and he was one of those advocating the foundation of an academy for the protection of scientific enterprise. Cowley's pamphlet on The Advancement of Experimental Philosophy, 1661, immediately preceded the foundation of the Royal Society; to which Cowley, in March 1667, at the suggestion of John Evelyn, addressed an ode. He died in the Porch House, in Chertsey, in consequence of having caught a cold while superintending his farm-labourers in the meadows late on a summer evening. On 3 August, Cowley was buried in Westminster Abbey beside the ashes of Chaucer and Spenser, where in 1675 the Duke of Buckingham erected a monument to his memory. His Poemata Latina, including six books "Plantarum," were printed in 1668. The poetry of Cowley rapidly fell into neglect.
The works of Cowley were collected in 1668, when Thomas Sprat brought out an edition in folio, to which he prefixed a life of the poet. There were many reprints of this collection, which formed the standard edition till 1881, when it was superseded by Alexander Balloch Grosart's privately printed edition in two volumes, for the Chertsey Worthies library. The Essays have frequently been revived. A Satire Against Separatists, printed in 1675, has been variously attributed to Cowley and to Peter Hausted.
During this same time, Cowley occupied himself in writing a history of the Civil War (which did not get published in full until 1973). In the preface to his 1656 Poems, Cowley mentioned that he had completed three books of an epic poem on the Civil War, but had left it unfinished after the First Battle of Newbury when the Royalist cause began to lose significant ground. In the preface Cowley indicated that he had destroyed all copies of the poem, but this was not precisely the truth. In 1697, twelve years after Cowley's death, a shortened version of the first book of the poem, called A Poem on the Late Civil War was published. It was assumed that the rest of the poem had indeed been destroyed or lost until the mid-20th century when scholar Allan Pritchard discovered the first of two extant manuscript copies of the whole poem among the Cowper family papers. Thus, the three completed books of Cowley's great (albeit unfinished) English epic, The Civill Warre (otherwise spelled "The Civil War"), was finally published in full for the first time in 1973.
The Mistress was the most popular poetic reading of the age, and is now the least read of all Cowley's works. It was the last and most violent expression of the amatory affectation of the 17th century, an affectation which had been endurable in Donne and other early Writers because it had been the vehicle of sincere emotion, but was unendurable in Cowley because in him it represented nothing but a perfunctory exercise, a mere exhibition of literary calisthenics. He appears to have been of a cold, or at least of a timid, disposition; in the face of these elaborately erotic volumes, we are told that to the end of his days he never summoned up courage to speak of love to a single woman in real life. The "Leonora" of The Chronicle is said to have been the only woman he ever loved, and she married the brother of his biographer, Sprat.