Henry Sidney
Sir Henry Sidney (1529 – 5 May 1586), Lord Deputy of Ireland, was the eldest son of Sir William Sidney of Penshurst, a prominent politician and courtier during the reigns of Henry VIII and Edward VI, from both of whom he received extensive grants of land, including the manor of Penshurst in Kent, which became the principal residence of the family.
Henry Sidney was brought up at court as the companion of Prince Edward, afterwards King Edward VI, and he continued to enjoy the favour of the Crown, serving under Mary I of England and then particularly throughout the reign of Queen Elizabeth I.
He was instrumental in the Elizabethan conquest of Ireland, serving as Lord Deputy three times.
His career was controversial both at home and in Ireland.
Barbara Sidney, Countess of Leicester
Barbara Sidney, Countess of Leicester( 1563 – 24 May 1621) was a Welsh heiress, and the first wife of Robert Sidney, 1st Earl of Leicester.
Philip Smythe, 2nd Viscount Strangford
Philip Smythe, 2nd Viscount Strangford (23 March 1634 – 8 August 1708) was an English politician who sat in the House of Commons in 1660.
Smythe was the son of Thomas Smythe, 1st Viscount Strangford of Westenhanger and Sturry, Kent and his wife Lady Barbara Sidney, the daughter of Robert Sidney, 1st Earl of Leicester.
He inherited the title on the death of his father in 1635.
In 1659 he was arrested at Canterbury, with his half brother Thomas Colepeper, following the uprising, and was released on parole and bail for £5,000.
In 1660, Smythe was elected Member of Parliament for Hythe in the Convention Parliament.
Smythe died at the age of 74.
Smythe married firstly his cousin Isabella Sidney, daughter of Robert Sidney, 2nd Earl of Leicester.
After her death in 1663, he married Mary, daughter of George Porter.
He was succeeded by his son Endymion.
Robert Sidney, 2nd Earl of Leicester
Robert Sidney, 2nd Earl of Leicester (1 December 1595 – 2 November 1677) was an English diplomat and politician who sat in the House of Commons between 1614 and 1625 and then succeeded to the peerage as Earl of Leicester.
Robert Sidney, 4th Earl of Leicester
Robert Sidney, 4th Earl of Leicester( 1649 – 11 November 1702) was the son of Philip Sidney, 3rd Earl of Leicester, and the former Lady Catherine Cecil.
Robert Sidney, 1st Earl of Leicester
Robert Sidney, 1st Earl of Leicester (19 November 1563 – 13 July 1626), second son of Sir Henry Sidney, was a statesman of Elizabethan and Jacobean England.
He was also a patron of the arts and an interesting poet.
His mother, Mary Sidney "née" Dudley, was a lady-in-waiting to Queen Elizabeth I and a sister of Robert Dudley, 1st Earl of Leicester, an advisor and favourite of the Queen.
Waleran de Beaumont, 1st Earl of Worcester
Waleran de Beaumont, Count of Meulan, 1st Earl of Worcester( 1104 – 9 April 1166, Preaux), was the son of Robert de Beaumont, 1st Earl of Leicester and Elizabeth de Vermandois, and the twin brother of Robert de Beaumont, 2nd Earl of Leicester.
He is not referred to by any surname in a contemporary document other than' Waleran son of Count Robert'.
Philip Sidney, 5th Earl of Leicester
Philip Sidney, 5th Earl of Leicester( 8 July 1676 – 24 July 1705) was a British peer and Member of Parliament for Kent, styled Viscount Lisle from 1698 to 1702.
He inherited the earldom from Robert Sidney, 4th Earl of Leicester and was succeeded by his brother John Sidney, 6th Earl of Leicester.
There is a memorial to him at St John the Baptist, Penshurst.
Jocelyn Sidney, 7th Earl of Leicester
Jocelyn Sidney, 7th Earl of Leicester( 1682 – 7 July 1743) was a British peer, known as Hon. Jocelyn Sidney until 1737.
He was the son of Robert Sidney, 4th Earl of Leicester and Lady Elizabeth Egerton.
He was educated at University College, Oxford University.
In 1734, he was appointed Chief Porter of the Tower of London by his older brother John Sidney, 6th Earl of Leicester, then Constable of the Tower.
He succeeded his brother in that year, but died without legitimate issue in 1743, when the titles of Earl of Leicester and Viscount Lisle became extinct.
Jocelyn's illegitimate daughter Lady Anne Sidney married Henry Streatfeild of Chiddingstone, Kent on 25 September 1752.
On Sir Jocelyn's death, Henry could potentially have inherited the Penshurst Estate, but after much legal wrangling Henry and Anne only received the income from the Sidneys' Welsh properties- but these were still fairly significant.
Gilbert Talbot, 3rd Baron Talbot
Gilbert Talbot, 3rd Baron Talbot( c. 1332–1387) was an English nobleman and soldier.
He was the grandfather of John Talbot, 1st Earl of Shrewsbury.

Question: Who is Robert Sidney, 1St Earl Of Leicester's paternal grandfather?
Answer: Sir William Sidney