Richard Marshal, 3rd Earl of Pembroke
Richard Marshal, 3rd Earl of Pembroke( 119116 April 1234), was the son of William Marshal, 1st Earl of Pembroke and brother of William Marshal, 2nd Earl of Pembroke, whom he succeeded to the Earldom of Pembroke and Lord Marshal of England upon his brother's death on 6 April 1231.
Anne Devereux
Anne Devereux, Countess of Pembroke( c. 1430 – after 25 June 1486), was an English noblewoman, who was Countess of Pembroke during the 15th century by virtue of marriage to William Herbert, 1st Earl of Pembroke.
She was born in Bodenham, the daughter of Sir Walter Devereux, the Lord Chancellor of Ireland, and his wife Elizabeth Merbury.
Anne's grandfather, Walter, was the son of Agnes Crophull.
By Crophull's second marriage to Sir John Parr, Anne was a cousin to the Parr family which included Sir Thomas Parr; father of King Henry VIII's last queen consort, Catherine Parr.
Agnes Mortimer, Countess of Pembroke
Agnes Mortimer, Countess of Pembroke (1317 – 25 July 1368) was the wife of Laurence Hastings, 1st Earl of Pembroke.
She was a daughter of Roger Mortimer, 1st Earl of March and Joan de Geneville, Baroness Geneville.
Joan de Munchensi
Joan de Munchensi or Munchensy( or Joanna), Lady of Swanscombe and Countess of Pembroke( c. 1230 – aft. 20 September 1307), was the daughter of Joan Marshal and granddaughter of William Marshal, 1st Earl of Pembroke and Isabel de Clare, 4th Countess of Pembroke" suo jure".
Maud Marshal
Maud Marshal, Countess of Norfolk, Countess of Surrey( 1192 – 27 March 1248) was an Anglo- Norman noblewoman and a wealthy co-heiress of her father William Marshal, 1st Earl of Pembroke, and her mother Isabel de Clare" suo jure" 4th Countess of Pembroke.
Maud was their eldest daughter.
She had two husbands: Hugh Bigod, 3rd Earl of Norfolk, and William de Warenne, 5th Earl of Surrey.
Maud was also known as Matilda Marshal.
Countess of Pembroke
Countess of Pembroke is a title that has been borne by several women throughout history, including:
Marie de St Pol
Marie de St Pol, Countess of Pembroke( c.1303–1377) was the wife of Aymer de Valence, 2nd Earl of Pembroke( c.1275-1324), and is best known as the foundress of Pembroke College, Cambridge.
Mary Woodville
Mary Woodville, Countess of Pembroke( c. 1456–1481) was a sister of Edward IV's Queen consort, Elizabeth Woodville, and of Anthony Woodville, 2nd Earl Rivers.
She later became the first wife of William Herbert, 2nd Earl of Pembroke, by whom she had one daughter.
Catherine Herbert, Countess of Pembroke
Catherine Herbert, Countess of Pembroke(" née" Yekaterina Semyonovna Vorontsova;; 24 October 1784 – 27 March 1856), was a Russian noblewoman who later married the Earl of Pembroke.
She was born in Saint Petersburg, the daughter of Count Semyon Vorontsov( sometimes spelled Woronzow), the Russian ambassador in Britain from 1785, and the only sister of Prince Mikhail Vorontsov, Viceroy of New Russia and Caucasus( 1782 – 1856).
She was also a niece of Princess Dashkova, a friend of Catherine the Great and a conspirator in the" coup d'état" that deposed Tsar Peter III and put his wife on the throne.
In 1808, she married Gen. George Herbert, 11th Earl of Pembroke as his second wife and became Countess of Pembroke, the châtelaine of Wilton House, Wiltshire.
The Wilton Estate, Salisbury, held an exhibition on her life titled" Through Russian Eyes" in August 2008.
Her letters show her to have been a shrewd observer of European politics.
Roger Mortimer, 1st Earl of March
Roger Mortimer, 3rd Baron Mortimer, 1st Earl of March (25 April 128729 November 1330), was an English nobleman and powerful Marcher lord who gained many estates in the Welsh Marches and Ireland following his advantageous marriage to the wealthy heiress Joan de Geneville, 2nd Baroness Geneville.
In November 1316, he was appointed Lord Lieutenant of Ireland.
He was imprisoned in the Tower of London in 1322 for having led the Marcher lords in a revolt against King Edward II in what became known as the Despenser War.
He later escaped to France, where he was joined by Edward's queen consort Isabella, whom he may have taken as his mistress.
After he and Isabella led a successful invasion and rebellion, Edward was deposed; Mortimer allegedly arranged his murder at Berkeley Castle.
For three years, Mortimer was "de facto" ruler of England before being himself overthrown by Edward's eldest son, Edward III.
Accused of assuming royal power and other crimes, Mortimer was executed by hanging at Tyburn.

Question: Why did Agnes Mortimer, Countess Of Pembroke's father die?
Answer: hanging