Elizabeth Cavendish was born in 1626, the second daughter of William Cavendish, later 1st Duke of Newcastle (1592-1676), and Elizabeth Bassett (d. April 1643) the widow of Henry Howard, Earl of Northampton. Elizabeth Cavendish enjoyed a privileged childhood and courtly education, largely in retirement at the family seat of Welbeck, Nottinghamshire . Her mother has left few traces beyond a splendid portrait (now in Kenwood House on Hampstead Heath in London); she was renowned for her piety. Her father was an important figure at court, appointed governor of the future Charles II in 1638. Despite his many absences on public business, William Cavendish doted on his children and took care over their education, as is apparent in a manuscript in which he exchanges playful verse dialogues with them (University of Nottingham MSS Portland Collection PwV 25 fol. 21-22).

On 22 July 1641 Elizabeth married John Egerton, then Viscount Brackley, from her father's London house. As children her husband and his siblings had acted in a number of masques, including Milton, 's Comus, written for the family and in 1637 dedicated to John Egerton in print. Marrying into the Egerton family connected Elizabeth to a number of formidable women, such as her husband's grandmother Alice Stanley, Dowager Countess of Derby, the pious Elizabeth, Countess of Huntingdon and the prophetess Lady Eleanor Douglas. The family were also closely touched by the scandals of the Earl of Castlehaven and his unfortunate family. After her marriage the young bride-who was "too young to be bedded" in her stepmother's opinion (Travitsky, 107)-remained at her father's seat of Welbeck. Welbeck was besieged and occupied several times by Parliamentary forces between 1644 and 1645, and Travitsky (64-67) speculates that it may have been during this turbulent time that Elizabeth collaborated with her elder sister Lady Jane Cheyne on a manuscript of poems, a pastoral, and a play dedicated to their father (Bodleian MS Rawlinson Poet 16 and Beinecke Osborn MS b.223 (an incomplete copy)). The manuscript offers important evidence of married gentlewomen using manuscript writing to maintain ties with their natal family (Ezell). Their mother had died in April 1643 and the social-climbing heroine of the sisters' play, The Concealed Fancies, may have become a comment on their father's growing romance with the heiress Margaret Lucas, to whom William Cavendish had written courtship "Phanseys". The couple married in December 1645, but the sisters never approved of their young and flamboyant stepmother; William and Margaret were never, for example, invited to stand as godparents for Elizabeth's nine children.

In 1649 John Egerton succeeded his father to become 2nd Earl of Bridgewater. During the Interregnum the Earl and Countess lived in retirement at the family seat of Ashridge in Buckinghamshire. In April 1651 John Egerton was imprisoned briefly as a royalist but was soon released on bail. The couple maintained connections with important royalist families, a number of whom stood as godparents for their children, including, on 31 March 1661, Charles II himself. The child was their last, Stuart, who was born 8 March 1660 and died unmarried. In 1662 John Egerton was appointed to manage the conference on the Act of Uniformity (DNB). During these years Elizabeth must have spent much of her time-that not devoted to her growing family-in meditation and religious study. She composed a volume of chapter-by-chapter meditations on the Bible, as well as a number of prayers and occasional meditations. On 12 June 1663 John Egerton was taken into custody for accepting a challenge from Lionel Cranfield, Earl of Middlesex, over the conduct of Cranfield's niece Elizabeth, Egerton's ward. Although Egerton was not long in custody the event nevertheless led to tragedy: his pregnant wife journeyed to visit him, fell into premature labour and died on 14 July 1663 (Travitsky, 115). The child, a son, was stillborn. In his grief her husband had an elaborate memorial constructed, along with fair copies made of her works to be preserved by the family. He had an incomplete fair copy (Huntington MS Z Early X Eng. 1620 LF 297343 (EL 8/G/8)) made of her draft Biblical meditations (Huntington MS EL 8374), along with several copies of her "loose papers", prayers and occasional meditations written throughout their married life (Huntington MS EL 8376; BL MS Egerton 607).

Biographical article by Erica Longfellow.

See also new ODNB entry for 'Egerton (nee Cavendish) Elizabeth, Countess of Bridgewater (1626-1663)'.