William Cavendish, first earl of Devonshire (1551–1626)

by unknown artist, 1576

Hardwick Hall, The Devonshire Collection (The National Trust). Photograph: Photographic Survey, Courtauld Institute of Art, London

Cavendish, William, first earl of Devonshire (1551–1626), nobleman, was born on 27 December 1551, the second son of Sir William Cavendish (1508–1557), administrator, of Chatsworth, Derbyshire, and his third wife, Elizabeth [see Talbot, Elizabeth, countess of Shrewsbury (1527–1608)], noblewoman, daughter and coheir of John Hardwick of Hardwick, Derbyshire, and his wife, Elizabeth. His godparents were Elizabeth Parr, marchioness of Northampton, William Paulet, first marquess of Winchester, and William Herbert, first earl of Pembroke. His two brothers were Henry Cavendish (1550–1616), soldier and traveller, and Sir Charles Cavendish (1553–1617), of Welbeck Abbey, Nottinghamshire. However, William Cavendish was his mother's favourite, especially from the 1580s onwards when she was disillusioned with his elder brother.

Sir William Cavendish died on 25 October 1557, and his widow married Sir William Saintloe on 14 December. Saintloe had William and Henry Cavendish educated at Eton College from 21 November 1560. William Cavendish matriculated from Clare College, Cambridge, on 29 September 1567. His mother, again a widow, married George Talbot, sixth earl of Shrewsbury (c. 1522–1590), magnate, about this time. In the marriage settlement Shrewsbury agreed to pay his new wife's debts and promised considerable sums to William and Charles Cavendish when they reached the age of twenty-one.

When Cavendish turned twenty-one Shrewsbury, because of the cost of the guardianship of Mary, queen of Scots, was not in a strong financial position. The countess of Shrewsbury agreed to absolve her husband from what he had promised to pay her and her children if he would legally return the lands she had originally brought to the marriage and give them to William and Charles Cavendish, with a discretionary life interest in them for herself. On 22 April 1572 Shrewsbury signed the deed of gift, something he was to regret later. During the same year William Cavendish was admitted to study law at Gray's Inn. He was possibly knighted in 1580, but the evidence is ambiguous. On 21 March 1581 he married Anne (d. before 1619), daughter and coheir of Henry Keighley of Keighley, Yorkshire, and his wife, Mary. The couple had three sons, including William Cavendish, second earl of Devonshire (1590–1628), nobleman, and three daughters. By 1584 the earl and countess of Shrewsbury were in conflict, and he claimed the rents from his wife's tenants in Derbyshire and Somerset. He raided Chatsworth, Derbyshire, and Cavendish barred the great doors while his mother fled. Cavendish, armed and surrounded by his loyal servants, faced his stepfather as he prepared to fight for his family's honour and inheritance. Elizabeth I commanded that they call off their feud, and royal officials took Cavendish to London, where he was briefly imprisoned in the Fleet. The queen then insisted on a full inquiry conducted by the lord chancellor, Sir Thomas Bromley, with Robert Dudley, earl of Leicester, acting as an informal mediator.

On both occasions when Cavendish was returned to parliament (for Liverpool in 1586 and for Newport in Monmouthshire in 1588), it was from boroughs remote from Derbyshire. This may have been because of Shrewsbury's enmity, the earl effectively blocking any local patronage for his stepsons. Quite possibly in 1585, at the height of the quarrel between the earl and countess of Shrewsbury, she considered it would be potentially helpful to have her son in parliament, and Sir Ralph Sadler arranged the election in 1586 as a favour. A royal commissioner investigated but trod warily because of Shrewsbury's power. The earl died in 1590 and the situation eased. Cavendish was named of the quorum about 1583. Chatsworth was legally entailed to Henry Cavendish and reverted to him at Shrewsbury's death. He was not on speaking terms with his mother, and she bought lands for William Cavendish valued at £15,900 by 1584. William Cavendish had little interest in life at court, but from 1595 to 1596 he was sheriff of Derbyshire, his local consequence being based on his status as a great landowner.

Cavendish became more prominent after the accession of James I in 1603. He was elevated to the peerage as Baron Cavendish of Hardwick on 4 May 1605. He inherited the bulk of his mother's land and property when she died on 13 February 1608 and bought Chatsworth from his elder brother in the following year. Cavendish managed his estates very carefully, promoted industrial enterprise, had a thorough understanding of finance, continued to purchase land, and was one of the first investors in Virginia and a co-grantee of the Bermuda Islands, with one of Bermuda's nine parishes named Devonshire after his most senior title. He also invested in the Russia Company, Somers Island Company, and North-West Passage Company, and very heavily but successfully in the East India Company. His local importance grew. He was named bailiff of Tutbury Castle, Staffordshire, custos rotulorum for Derbyshire in 1615, and, jointly with his heir, lord lieutenant of Derbyshire from 1619. Cavendish succeeded his elder brother on 12 October 1616, acquiring more property, and was promoted earl of Devonshire on 7 August 1618. This title was acquired after some unedifying petitioning of Arabella Stuart and cost Cavendish £10,900 in total. Devonshire married again by 1619, his second wife being Elizabeth (d. c.1642), daughter and heir of Edward Boughton of Cawston, Warwickshire, and his wife, Susanna, and widow of Sir Richard Wortley. They had one son. Devonshire died at Hardwick Hall on 3 March 1626 and was buried in the parish church at Edensor. Leaving his heir about 100,000 acres, he had consolidated his own inheritance and laid the foundation for one of the greatest estates of the seventeenth century.