Early life

'A true relation' paints a picture of a secure and harmonious family, whose happiness was shattered by civil war. Margaret's widowed mother is depicted as being 'of a grave Behaviour, and [of] such a Magestick Grandeur' that the common people held her in awe (Cavendish, True relation, 48). Her mother managed what came to her by jointure with little or no male help and provided Margaret with an example of how a woman might act to protect family interests. For instance, she was effective in shielding her son's inheritance from the court of wards by using the political connections of her son-in-law, Peter Killigrew. The family lived for about half the year in Colchester and the other half in London, enjoying the pleasures of 'Spring-garden, Hide-park, and the like places' (ibid., 45). Margaret's education was somewhat rudimentary; she had private tutors for 'all sorts of virtues, such as singing, dancing, playing on music, reading, writing [needle] working, and the like', but this may have been merely the 'ancient decayed gentlewoman', who taught her to read and write (Grant, 37). Her brother John Lucas, later first Baron Lucas of Shenfield (1606–1671), seems to have been a contentious Colchester landowner rather than a carefree youth. His antagonism towards the lower orders may have provided the motivation for a raid on his home during the Stour valley riots on 22 August 1642 when he attempted to leave his house to join Charles I with men and supplies.

It may have been the dangers of war which caused Margaret to leave Colchester to live in Oxford with her sister Catherine Pye in the autumn of 1642. It is likely that her mother hoped that Margaret would find a place at court, then resident in Oxford. In 1643 Margaret became a maid of honour to Queen Henrietta Maria, and in 1644 accompanied the queen into exile in Paris.

Marriage

In 'A true relation' Margaret says that she was bashful and painfully shy at court, qualities perhaps reflected in her plays, as with the character Lady Bashful in Love's Adventures (1662). Nevertheless, it was at court in Paris that Margaret met her future husband, William Cavendish, marquess of Newcastle upon Tyne (bap. 1593, d. 1676), a widower whose first wife had died in 1643. He was also the defeated royalist commander at Marston Moor, and had left England in July 1644 and arrived in Paris in April 1645. After a courtship that was opposed by Henrietta Maria and many of his friends, they were married in late November or early December 1645 by the future bishop John Cosin, in the private chapel of the English resident at the French court, Sir Richard Browne. They had no children, though some effort was made by the physician Richard Farrer to treat her failure to conceive. The court physician, Sir Theodore Mayerne, examined her for 'general ill-health' and dissuaded Newcastle from further fertility treatments. Five of Newcastle's children from his first marriage had survived infancy, two of whom wrote The Concealed Fancies (c.1645), a comedy poking good-natured fun at the newly-weds. Margaret's marriage portion was £2000, but that could not be paid immediately. The bride and groom moved to Rotterdam, staying there for six months before moving to Antwerp and leasing a house from the widow of the painter Peter Paul Rubens. In August 1648 her brother Sir Charles Lucas (1612/13–1648) was summarily executed after the siege of Colchester. In November 1651 Margaret travelled to England with her brother-in-law, Sir Charles Cavendish, hoping to gain something from her husband's sequestered estates by appealing to the committee for compounding. The committee denied her request on 10 December 1651 because she had married her husband after he had become a delinquent and because he was, in their view, 'the greatest traitor to the state' (Calendar of the Proceedings of the Committee for Compounding). While in England, presumably awaiting the outcome of Sir Charles Cavendish's attempt to compound, Margaret published Poems and Fancies (1653; rev. edns, 1664 and 1668), the first edition containing verse descriptions of her atomic theory, which resembles that of Walter Charleton. Her atomism is derived from Epicurus and her use of poetry to explain her views aligns with Lucretius's notion that poetry can produce intellectual pleasure, the highest good. However, Philosophical Fancies (1653) repudiates her atomic theory. Her work certainly made an impact. In April 1653 Dorothy Osborne wrote to William Temple commenting on this event and Margaret's eccentric sense of dress: 'a book of Poems newly come out, made by Lady Newcastle … tis ten times more Extravagant then her dresse' (Osborne, 75). The following month Osborne opined to the same correspondent that there were 'many soberer People in Bedlam' (ibid., 79).

After spending eighteen months in England, Margaret returned to Antwerp, where according to her later writings they endured some financial hardship. Nevertheless, Margaret continued to write and publish. The World's Olio (1655; repr. 1671) is a collection of brief observations on a wide variety of topics and includes caustic remarks on historical and mythological figures. Philosophical and Physical Opinions (1655; rev. edn, 1663) explains her materialist natural philosophy. Margaret agrees with Hobbes that incorporeal substance makes no sense and that all natural change involves change in motion. In her 'mature philosophy' she parts company with Hobbes, believing that change in motion is not caused by external forces but rather by 'vital agreement or sympathetic influence of parts, as within a single organism' (O'Neill, 261). In 1668 she reworked the second edition as Grounds of Natural Philosophy in a more tentative and plainer style than the original. Nature's Pictures (1656; rev. edn, 1671) is mostly a collection of love stories in verse and prose, which considers issues of sex and gender. There is, in addition, satire on disparate topics, such as the use of tobacco. The first edition contains the much-cited autobiography, 'A true relation', which was not reprinted in the second edition because she believed it lessened her dignity.

Newcastle followed Charles II back to England at the Restoration. She returned shortly afterwards and was evidently disappointed that her husband had failed to obtain the court office she thought he deserved. The Lotterie may have been written by Margaret at this time for a private royal performance, as part of a plan to secure royal favour. Margaret has been confused with the M. Cavendish who was a member of Katherine Philips's Society of Friendship, but this was Lady Mary Butler, a daughter of the first duke of Ormond, who after her marriage to William, Lord Cavendish, in 1662 was known as Lady Mary Cavendish, until her husband succeeded as fourth earl of Devonshire in 1684. In September 1660 Newcastle secured the passage of an act restoring his estates. This improvement in Newcastle's finances allowed Margaret to secure the first of many improvements to her jointure to £1125 per annum and a life interest in Bolsover Castle. Margaret and her husband left London towards the end of 1660. Retirement in the country suited Margaret's temperament and accorded well with the image of voluntary seclusion that became a staple of her self-presentation.

More works were to follow from Margaret's country retreat. Plays (1662), like Nature's Pictures, considers issues of sex and gender, often in the context of courtship and marriage. It includes Bell in campo which contains a woman who goes to war and in so doing recalls the 'Assaulted and Pursued Chastity' found in Nature's Pictures. Margaret, according to Battigelli, thought of herself in terms of a military leader and understood Henrietta Maria to be an example of a woman who led an army. Margaret's Orations of divers sorts (1662; 2nd edn, 1668) contains exemplary speeches to be delivered on set occasions. It includes 'Female orations' in which she explores the following questions without resolving them. Are women in fact subordinate to men in society? If so, is the cause of this insubordination a natural inequality between the sexes or a lack of opportunity for women, particularly as regards education? CCXI sociable Letters (1664) contains readable, mostly fictional letters addressed by one woman to another, sometimes cast as brief essays and sometimes in the form of small narratives or dialogues. In many cases the letters function as commentary on marriage, infidelity, and divorce, and they frequently offer women warnings against marriage, similar to those to be seen in Margaret's other works. Philosophical Letters (1664) critiques the writings of René Descartes, J. B. van Helmont, Thomas Hobbes, and Henry More. Prior to this volume Margaret had not engaged in direct dispute with other philosophers. Observations upon Experimental Philosophy (1666; repr., 1668) attacks Robert Hooke's Micrographia and contains 'The description of a new blazing world', a much discussed work of science fiction notable for its depiction of Margaret as two separate but interacting characters: an empress and the duchess of Newcastle. This was published as a separate edition in 1668 entitled The Description of a New World, called the Blazing-World.

During the 1660s Margaret became more actively involved in the running of the ducal estate. She exerted her influence in part directly and in part through the management of Francis Topp, who had married her maid-in-waiting and confidante, Elizabeth Chaplain. The increase in estate revenues saw Margaret acquire further improvements to her jointure in January 1668, when the additions included the mansion at Clerkenwell, and two augmentations in 1670. Other family members, including Newcastle's daughter Lady Jane Cheyne, felt that this was a ploy to better herself financially in expectation of the duke's death.

In 1667 Margaret and Newcastle made a visit to London. Increasingly, he had become known as a playwright, with two pre-war plays being revived successfully in the 1660s. In spring 1667 his new play The Humorous Lovers was produced. Further, The Life of William Cavendish (1667; repr., 1675, and translated as De vita et rebus gestis principis Guilielmi Duicis Novo-castrensis in 1668) was due to come into print that year, and they both may have wanted to use the visit to call attention to its publication. The Life was a canny apologia for her husband's military career and a description of life in exile in Antwerp, which has been much used by historians. On 23 May she received an invitation to visit the Royal Society, duly attending on 30 May to watch the scientific demonstrations offered her by such notables as Robert Boyle and Robert Hooke, and generally impressing the members of the society. Margaret, more than Newcastle, was the centre of attention during the visit to London. Samuel Pepys compared her to Queen Kristina of Sweden, who was known for her cross-dressing. That comparison was apt, for Sir Charles Lyttelton, writing of a visit made by the duke and duchess of York to Nottinghamshire in August 1665, noted that Margaret 'was dressed in a vest, and instead of courtesies, made legs and bows' (Grant, 184). During the trip to London she met again Mary Evelyn, wife of the diarist and daughter of Sir Richard Browne, who 'was surprised to find so much extravagancy and vanity in any person not confined within four walls'. Evelyn found Margaret's speech full of 'oaths and obscenity' and suggested that she was a flirt, or at least 'more than necessarily submissive' where men were concerned. Margaret often wrote about her love of creating unusual fashions in dress for herself and there is ample evidence that she was taken to be a physically attractive woman throughout her life. Even Mary Evelyn admitted that she had 'a good shape, which she may truly boast of' (Diary and Correspondence, 731). Pepys concurred, spotting her on 26 April 1667 while in her coach 'naked necked, without anything about it, and a black juste-au-corps; she seemed to me a very comely woman' (Pepys, 8.186–7).

Margaret continued to publish work following her sojourn in London. Plays Never before Printed (1668) continues themes found in her first collection of plays. In addition, it sometimes ridicules the Restoration rake hero, rejecting this figure in favour of a less cynical and more sincere lover. Thus the crass Monsieur Take-Pleasure in The Convent of Pleasure is held up to scorn and the sincere, if cross-dressed, Prince is praiseworthy. Margaret, in this play, as elsewhere in her fiction and drama, inverts or transforms plots found in Shakespeare's plays. In the case of The Convent, the circumstances of the male and female Love's Labour's Lost are exchanged.

Margaret Cavendish died on 15 December 1673 at her home, Welbeck Abbey, Nottinghamshire, and was buried in London on 7 January 1674 in Westminster Abbey. In addition to ordering an elaborate funeral procession that wound through the streets of London, her husband arranged to have a volume of letters and poems published in her honour, Letters and Poems in Honour of the Incomparable Princess, Margaret, Duchess of Newcastle (1676).

Reputation

It is difficult to gauge what Margaret's literary reputation was during her lifetime. Osborne says no more on the subject than is quoted above, and others, for the most part, discuss the writer but pay scant attention to the work. Bathsua Makin, writing in the year of Margaret's death, probably was more interested in the current state of education for women than in her achievements, when she wrote, 'the present Dutchess of New-Castle, by her own genius, rather than any timely instruction, over-tops many grave Grown-men' (Makin, An Essay to Revive the Antient Education of Gentlewomen, 1673, repr. 1980, 10). The Life of William Cavendish was read carefully by some contemporaries. It was used as a source by the historian John Rushworth and was employed as a model by Lucy Hutchinson for her life of her own husband. Elizabeth Pepys recommended it to Samuel Pepys on 18 March 1668. It was reprinted once shortly after the death of the duke, and it is likely that the publisher expected to make a profit from sales rather than from any subsidy. Margaret's other books were not so reprinted.

By the middle of the eighteenth century a shift took place in the literary world by which Margaret came to be seen as a harmless, even delightful eccentric, who produced affecting verse on the subject of moods and fairy folk. Her scientific writing, when mentioned, was regarded from an amused distance, or occasionally ridiculed. In The Connoisseur (22 May 1755), George Colman the elder and Bonnell Thornton suggest that her poem on melancholy was used by Milton in 'Il penseroso', a suggestion qualified in later editions but often repeated in biographical notes elsewhere. George Ballard's Memoirs of Several Ladies of Great Britain (1752) popularized selected poems, and anthologists of women's poetry generally followed his lead until the end of the nineteenth century. Horace Walpole in A catalogue of the royal and noble authors (1758) treated her literary output with a good deal of scepticism, while Charles Lamb, writing in 'Mackery End', in Essays of Elia (1823), became known as the champion of what he took to be a delightfully fanciful poet.

Towards the end of the nineteenth century, Margaret, the poet of moods and fairy folk, was supplanted by the loyal wife who suffered with her husband in exile and who recorded his war years in The Life of William Cavendish. First M. A. Lower and soon afterwards C. H. Firth produced editions of the Life, both of which were frequently reissued. Firth's footnotes confirm Margaret's understanding of the facts of the civil wars in the details of dates and troop movements. At about the same time she became the subject of several biographies. Early twentieth-century treatments of the novel often note that studies of character found in Sociable Letters adumbrate what is to be seen in eighteenth-century fiction. It was customary for those who wrote about her during the twentieth century to remark that she was called Mad Madge of Newcastle during her lifetime, but it is more likely that the label developed later, perhaps by connection with Mad Madge Murdockson from Sir Walter Scott's Heart of Midlothian.

Today Margaret is read by three overlapping groups: those who have an interest in sex and gender in the seventeenth century, especially as the two connect to politics; historians of science; and historians of drama, particularly in performance. Many feminists find her writing to be a puzzling mix of proto-feminist and traditional positions, but feminists have become less likely in the last few years to see her as a bad writer whose bad writing derives from a patriarchal society. Rather, she is seen as a good writer who overcame the impediments of patriarchy to produce books that are ironic, suggestive, and discursive—as opposed to contradictory, vague, and lacking in structure. Historians of science and those who trace the relationship between science and literature also see her as an important writer. John Rogers believes that her connection to the vitalist movement is similar to Milton's, asserting that 'both writers find themselves in often untenable literary binds as they struggle to accommodate divergent and contradictory forms of sanctioned truth' (Rogers, 181). In the case of Margaret the contradiction (or perhaps ambivalence) that is most bothersome today is her unwillingness to decide whether women have essentially the same intellectual capacity as men or are naturally men's intellectual inferiors. Historians of drama have been intent on experimenting with the production and recording on videotape of her plays, which were once considered unactable. The Blazing World is widely available and read. Margaret's defence of Shakespeare (Sociable Letters, letter 123), the first extended treatment of that playwright by any writer, is also beginning to gain recognition.