Question: In what year was the father of Elizabeth Capell, Countess of Essex born?

Context articles: Algernon Percy, 10th Earl of Northumberland
William Jennings Capell
Elizabeth Hay, Countess of Erroll
Sarah, Countess of Essex
Lettice Knollys
Adele Capell, Countess of Essex
Paul Capell, 11th Earl of Essex
Frances Walsingham
Henry Capell (MP for Hertfordshire)
Elizabeth Capell, Countess of Essex

Algernon Percy, 10th Earl of Northumberland, 4th Baron Percy, KG (29 September 1602 – 13 October 1668) was an English military leader and a prominent supporter of the Parliamentary cause in the English Civil War.
William Jennings "Bill" Capell (born 9 August 1952), a retired grocery clerk from Yuba City, California, is the heir presumptive to the Earldom of Essex.
 He will be the 12th Earl if the current earl, Paul Capell, 11th Earl of Essex (currently 71 and unmarried), dies without legitimate male issue.
 He had considered renouncing the earldom if it would require him to give up his United States citizenship.
 (Under the United Kingdom's Peerage Act 1963, a person may disclaim a hereditary peerage.)
 United States law requires only government officeholders without Congressional authorization and persons wishing to become naturalized citizens, however, to renounce titles of nobility.
 As Mr. Capell is in neither category, there would be no legal impediment to his use of the title as a U.S. citizen; indeed there is precedent in the case of the Earl of Wharncliffe, currently a Maine construction worker.
Elizabeth Hay, Countess of Erroll (17 January 1801 – 16 January 1856; born Elizabeth FitzClarence) was an illegitimate daughter of King William IV of the United Kingdom and Dorothea Jordan.
 She married William Hay, 18th Earl of Erroll, and became Countess of Erroll on 4 December 1820 at age 19.
 Due to Hay's parentage, William Hay became Lord Steward of the Household.
 Elizabeth and William Hay married at St George's, Hanover Square.
 Hay is pictured in a FitzClarence family portrait in House of Dun and kept a stone thrown at her father William IV and the gloves he wore on opening his first Parliament as mementos.
 She died in Edinburgh, Scotland.
Sarah Bazett (died 16 January 1838) ("Sarah, Countess of Essex"), ("alias" Sarah Capel; Sarah, Lady Malden) was a talented and prolific amateur artist, generally known as "Sarah, Countess of Essex" who specialised in making watercolour copies of old portraits of 16th century personages and other paintings, and her surviving copies in many instances are the only evidence of the now lost originals.
 Over a hundred of her portraits in watercolour and gouache on paper were published in the 1825 edition of Lucy Aikin's "Memoirs of the Court of Queen Elizabeth", first published in 1818 as a two-volume work and re-issued in several editions (4th edition 1819, further edition 1823).
 She was knowledgeable in the field of heraldry and frequently added the subject's coat of arms and other heraldic devices to her copy portraits.
Lettice Knollys ( , sometimes latinized as Laetitia, alias Lettice Devereux or Lettice Dudley), Countess of Essex and Countess of Leicester (8 November 1543 – 25 December 1634), was an English noblewoman and mother to the courtiers Robert Devereux, 2nd Earl of Essex, and Lady Penelope Rich, although via her marriage to Elizabeth I's favourite, Robert Dudley, Earl of Leicester, she incurred the Queen's unrelenting displeasure.
Adele Capell, Countess of Essex (née Adele Grant) was a US-born socialite who married into the British nobility.
Frederick Paul de Vere Capell, 11th Earl of Essex (born 29 May 1944) is the current Earl of Essex.
 He succeeded his father Robert Capell, 10th Earl of Essex, in 2005.
Frances Walsingham, Countess of Essex and Countess of Clanricarde (1567 – 17 February 1633) was an English noblewoman.
 The daughter of Sir Francis Walsingham, Elizabeth I's Secretary of State, she became the wife of Sir Philip Sidney at age 16.
 Her second husband was The 2nd Earl of Essex, Queen Elizabeth's favourite, with whom she had five children.
 Shortly after his execution in 1601, she married her lover, The 4th Earl of Clanricarde, and went to live in Ireland.
Henry Capell (born before 1537 – 1588), of Little Hadham, Hertfordshire and Rayne, Essex, was an English politician.
Elizabeth Capell, Countess of Essex (1 December 1636 – 5 February 1718; née Percy) was an English noblewoman, the daughter of Algernon Percy, 10th Earl of Northumberland.
 She was the wife of Arthur Capell, 1st Earl of Essex.
 Elizabeth was the subject of a portrait by court painter Sir Peter Lely.