Biography of Agnes Mortimer Countess of Pembroke 1317-1368
Paternal Family Tree: Mortimer
Maternal Family Tree: Jeanne Fougères Countess Lusignan Countess La Marche and Angoulême
1328 Mortimer Double Marriage and Tournament
1328 Roger Mortimer created Earl of March
On 20 Sep 1301 [her father] Roger Mortimer 1st Earl March (age 14) and [her mother] Joan Geneville Baroness Mortimer 2nd Baroness Geneville (age 15) were married. They were third cousin once removed. He a great x 3 grandson of King John "Lackland" of England. 
In Jul 1304 [her grandfather] Edmund Mortimer 2nd Baron Mortimer of Wigmore (age 53) died at Wigmore Castle, Herefordshire [Map]. He was buried at Wigmore Abbey [Map]. His son [her father] Roger Mortimer 1st Earl March (age 17) succeeded 3rd Baron Mortimer of Wigmore. [her mother] Joan Geneville Baroness Mortimer 2nd Baroness Geneville (age 18) by marriage Baroness Mortimer of Wigmore.
On 21 Oct 1314 Geoffrey Geneville 1st Baron Geneville (age 88) died at Trim County Meath. He was buried at Black Friary, Trim, County Meath. His granddaughter [her mother] Joan Geneville Baroness Mortimer 2nd Baroness Geneville (age 28) succeeded 2nd Baroness Geneville. She and her husband [her father] Roger Mortimer 1st Earl March (age 27) inherited the vast legacy of the de Lacy dynasty, including Ludlow Castle [Map].
In 1317 Agnes Mortimer Countess of Pembroke was born to Roger Mortimer 1st Earl March (age 29) and Joan Geneville Baroness Mortimer 2nd Baroness Geneville (age 30).
On 20 Jan 1325 John Hastings 2nd Baron Hastings 14th Baron Bergavenny (age 38) died. His son [her future husband] Laurence Hastings 1st Earl Pembroke (age 5) succeeded 3rd Baron Hastings, 14th Baron Bergavenny Feudal Creation.
Around 1326 Ralph Stafford 1st Earl Stafford (age 24) and [her future sister-in-law] Katherine Hastings Baroness Stafford (age 22) were married. She by marriage Baroness Stafford. She the daughter of John Hastings 2nd Baron Hastings 14th Baron Bergavenny and Juliana Leybourne Countess Huntingdon (age 23).
On 31 May 1328 the Mortimer family leveraged their new status at a lavish ceremony that celebrated the marriages of two of Roger Mortimer's (age 41) daughters at Hereford [Map].
Edward Plantagenet (age 8) and Beatrice Mortimer (age 6) were married. She the daughter of Roger Mortimer 1st Earl March (age 41) and Joan Geneville Baroness Mortimer 2nd Baroness Geneville (age 42). He the son of Thomas of Brotherton 1st Earl Norfolk (age 27) and Alice Hales Countess Norfolk. They were half third cousin once removed. He a grandson of King Edward "Longshanks" I of England. She a great x 4 granddaughter of King John "Lackland" of England. 
Laurence Hastings 1st Earl Pembroke (age 9) and Agnes Mortimer Countess of Pembroke (age 11) were married. She the daughter of Roger Mortimer 1st Earl March (age 41) and Joan Geneville Baroness Mortimer 2nd Baroness Geneville (age 42). He the son of John Hastings 2nd Baron Hastings 14th Baron Bergavenny and Juliana Leybourne Countess Huntingdon (age 25). They were third cousin once removed. She a great x 4 granddaughter of King John "Lackland" of England.
King Edward III of England (age 15) and his mother Isabella of France Queen Consort England (age 33) attended as well as Roger Mortimer 1st Earl March (age 41).
In Oct 1328 [her father] Roger Mortimer 1st Earl March (age 41) was created 1st Earl March by his own authority to the surprise, perhaps astonishment, of the nobility who compared his behaviour as similar to the usurped Edward II.
On 29 Nov 1330 [her father] Roger Mortimer 1st Earl March (age 43) was hanged naked at Tyburn [Map] accused of assuming royal power and of various other high misdemeanours. His body hung at the gallows for two days and nights. He was buried at Christ Church Greyfriars [Map]. Isabella of France Queen Consort England (age 35) subsequently requested his burial at Wigmore Abbey [Map] and, after firstly refusing, King Edward III of England (age 18) allowed his remains to be removed to Wigmore Abbey [Map]. His grandson Roger Mortimer 2nd Earl March (age 2) succeeded 2nd Earl March, 4th Baron Mortimer of Wigmore.
On 06 Jul 1336 [her sister-in-law] Katherine Hastings Baroness Stafford (age 32) died at Stafford, Staffordshire [Map].
In 1339 [her husband] Laurence Hastings 1st Earl Pembroke (age 19) was created 1st Earl Pembroke. Agnes Mortimer Countess of Pembroke (age 22) by marriage Countess Pembroke.
On 29 Aug 1347 [her son] John Hastings 2nd Earl Pembroke was born to [her husband] Laurence Hastings 1st Earl Pembroke (age 28) and Agnes Mortimer Countess of Pembroke (age 30) at Sutton Valence, Maidstone.
On 20 Aug 1348 [her husband] Laurence Hastings 1st Earl Pembroke (age 29) died at Abergavenny Castle [Map]. He was buried at Abergavenny Priory [Map]. His son [her son] John Hastings 2nd Earl Pembroke succeeded 2nd Earl Pembroke, 4th Baron Hastings, 15th Baron Bergavenny Feudal Creation.
On 19 Oct 1356 [her mother] Joan Geneville Baroness Mortimer 2nd Baroness Geneville (age 70) died. She was buried at Wigmore Abbey [Map].
Archaeologia Volume 35 1853 XXXIII. On the 15th of December [1357] the Queen (age 62) was visited by the Countess of Pembroke (age 40), who passed the entire day with her; and, from the frequency of her subsequent visits, it would appear that she was one of Isabella's closest friends. And, again, what can we infer but a clinging on her part to the memory of her lover, when we find that this lady, widow of Lawrence Hastings, Earl of Pembroke, was none other than Agnes, daughter of Mortimer himself; and that we thus have recorded visits received by Isabella of a daughter, the grandson, and grandson's brother-in law of her favourite, within the space of one month?
Archaeologia Volume 35 1853 XXXIII. On the 10th and 11th of January, 1358, Isabella (age 63) is visited by the Countess of Pembroke (age 41), the Countess of Kent (age 28), and Sir John de Wynewyk. Of these, the Countess of Pembroke has been already noticed. The Countess of Kent was Isabella (age 28), daughter of the Marquess of Juliers (age 59), and widow of John Plantagenet, Earl of Kent. Her husband had died in the year 13531; upon which she took the veil at Waverley [Map]; but afterwards, as Dugdale tells us, "quitting her profession, was clandestinely married to Sir Eustace Dabrischecourt." The name of this knight is usually written D'Ambreticourt. He was the son of Sir Sanchez D'Ambreticourt (age 28), Knight of the Garter, and a descendant of the poor knight of Ostrevant, in Hainault, in whose house Isabella found shelter on her dismissal from the court of her brother, Charles IV. of France, and whom, with his whole family, she had invited over into England, and had in various ways advanced. In reference to the Countess of Kent, Froissart says— "This lady was greatly attached to Sir Eustace D'Ambreticourt, for his gallant deeds of arms, which had been related to her: and she sent him coursers, hackneys, and letters full of love; which so much emboldened Sir Eustace, and spurred him to perform such feats of chivalry and of arms, that all those under him made fortunes." Dugdale tells us, in respect of the Countess's breach of her vows, that "she and her said husband, being personally convented before the said Archbishop of Canterbury in his manor house of Maghfeld," the Archbishop imposed on them a certain penance of prayers and alms very skilfully adapted to their offence.
Of Sir John de Wynewyk, I have been unable to learn anything of certainty. He appears to have been attached to the King's court, and was perhaps the medium employed for managing Isabella's affairs. He visited her and exchanged letters with her constantly.
Note 1. Possibly a mistake for 1352? John Plantagenet 3rd Earl Kent died 26 Dec 1352.
Archaeologia Volume 35 1853 XXXIII. On the 21st [Mar 1358], William, Archbishop of Sens, now in England to negotiate a treaty of peace for his Sovereign with the English Monarch, the Maréchal D'Audenham, and the Countess of Pembroke (age 41), spend the entire day with Isabella (age 63); and her grandson, the Earl of Richmond (age 18), arrives to supper.
Archaeologia Volume 35 1853 XXXIII. On the 12th [Apr 1358], the Countess of Pembroke (age 41) again came to dinner.
Archaeologia Volume 35 1853 XXXIII. Reverting to the notices of visitors from the time of the Queen's leaving Hertford, we find that on the 17th of April [1358], in London, the Maréchal D'Audenham passed the entire day with her; the Countess of Pembroke (age 41) and Sir John de Wynewyk coming to supper.
Archaeologia Volume 35 1853 XXXIII. On the 18th [Apr 1358], also in London, the Countess of Pembroke (age 41), the Earl of Ponthieu (age 39) (another of the captives of Poitiers), and the Maréchal D'Audenham came to dinner— "et plures comites et barones post prandium.1".
Note 1. "and several counts and barons after dinner"
Archaeologia Volume 35 1853 XXXIII. The following visits, during her [Isabella of France Queen Consort England (age 63)] stay in London, are recorded. On the 30th of April, the Countess of Warren to supper (age 62). On the 1st of May, the Countess of Pembroke (age 41) to dinner; and the King after dinner. On the 2nd of May, the Countesses of Warren (age 62) and Pembroke (age 41) to dinner; and the King (age 45), the Prince of Wales (age 27), the Earl of March (age 29), and others, after dinner. On the 3rd of May, the Countess of Pembroke (age 41) and the Maréchal D'Audenham to dinner; and the Earl of Arundel (age 52), "et plures magnates Franciæ1," after dinner. On the 4th, the Count of Tancarville to dinner. On the 5th, the Countesses of Warren and Pembroke and the Maréchal D'Audenham again to dinner; and the Chancellor of England and many French noblemen after dinner. On the 6th the Chief Justice and the Barons of the Exchequer to dinner. On the four following days, the Countesses of Warren, Kent, and Pembroke dine with the Queen; and on the last of the four Sir John de Wynewyk comes to supper. On the 11th, Queen Philippa (age 43) appears to have dined with Isabella, but the entry is partially obliterated; the Earl Marshal and other noblemen came after dinner. On the 12th, the Countess of Pembroke dined, and the Cardinals ( of Périgord and St. Vitalis ), the Archbishop of Sens, and some French noblemen came after dinner. On Sunday the 13th, the Countess of Warren and others from London, as it is expressed, dined; and the King of France, the Chancellor of England, and others, visited the Queen after dinner.
Note 1. and several magnates of France.
Archaeologia Volume 35 1853 XXXIII. On the 24th [May 1358], the Countess of Pembroke (age 41) and some Scottish noblemen came to dinner.
Archaeologia Volume 35 1853 XXXIII. On the 2nd of June [1358], the Countess of Pembroke (age 41) came to dinner.
Archaeologia Volume 35 1853 XXXIII. On the 19th [1358], the Countess of Pembroke (age 41) spent the entire day at the castle [Map]; and Sir John de Wynewyk came to supper.
On 19 May 1359 , or thereabouts, a double-royal wedding celebration took place at Reading Abbey [Map] whereby two children of King Edward III of England (age 46) were married:
John of Gaunt 1st Duke Lancaster (age 19) and Blanche Plantagenet Duchess Lancaster (age 14) were married. She by marriage Countess Richmond. She the daughter of Henry of Grosmont 1st Duke Lancaster (age 49) and Isabel Beaumont Duchess Lancaster (age 39). He the son of King Edward III of England (age 46) and Philippa of Hainault Queen Consort England (age 44). They were half second cousin once removed. She a great x 2 granddaughter of King Henry III of England. 
[her son] John Hastings 2nd Earl Pembroke (age 11) and [her daughter-in-law] Margaret Plantagenet Countess of Pembroke (age 12) were married. At the time John Hastings 2nd Earl Pembroke (age 11) was a ward of King Edward III of England (age 46) who would enjoy the benefit of the substantial revenue of the Earldom of Pembroke until John came of age nine years later in 1368. She died two or so years later probably of plague. She the daughter of King Edward III of England (age 46) and Philippa of Hainault Queen Consort England (age 44). He the son of Laurence Hastings 1st Earl Pembroke and Agnes Mortimer Countess of Pembroke (age 42). They were half fourth cousins. He a great x 5 grandson of King John "Lackland" of England.
In 1368 Agnes Mortimer Countess of Pembroke (age 51) died.
Archaeologia Volume 35 1853 XXXIII. On the 20th of April, at Shene [Map], the Earl of Tancarville, the Countesses of Pembroke and Warren, "et alii magnates1," dined with the Queen.
Note 1. "and other magnates".
Kings Wessex: Great x 10 Grand Daughter of King Edmund "Ironside" I of England
Kings Gwynedd: Great x 5 Grand Daughter of Owain "Great" King Gwynedd
Kings Seisyllwg: Great x 11 Grand Daughter of Hywel "Dda aka Good" King Seisyllwg King Deheubarth
Kings Powys: Great x 6 Grand Daughter of Maredudd ap Bleddyn King Powys
Kings England: Great x 4 Grand Daughter of King John "Lackland" of England
Kings Scotland: Great x 8 Grand Daughter of Malcolm III King Scotland
Kings Franks: Great x 15 Grand Daughter of Louis "Pious" King Aquitaine I King Franks
Kings France: Great x 6 Grand Daughter of Louis "Fat" VI King France
Great x 4 Grandfather: Hugh Mortimer
Great x 3 Grandfather: Roger Mortimer
Great x 4 Grandmother: Matilda Gernon
Great x 2 Grandfather: Ralph Mortimer
Great x 4 Grandfather: Walchelin Ferrers
Great x 3 Grandmother: Isabel Ferrers
Great x 1 Grandfather: Roger Mortimer 1st Baron Mortimer of Wigmore Great Grand Son of King John "Lackland" of England
Great x 4 Grandfather: Iorwerth "Drwyndwn aka Flat Nosed" Aberffraw
Great x 3 Grandfather: Llewellyn "The Great" Aberffraw
Great x 4 Grandmother: Marared ferch Madog Mathrafal
Great x 2 Grandmother: Gwladus verch Llewelyn "Dark Eyed" Aberffraw Grand Daughter of King John "Lackland" of England
Great x 4 Grandfather: King John "Lackland" of England Son of King Henry "Curtmantle" II of England
Great x 3 Grandmother: Joan Plantagenet Daughter of King John "Lackland" of England
Great x 4 Grandmother: Adela Plantagenet
GrandFather: Edmund Mortimer 2nd Baron Mortimer of Wigmore 2 x Great Grand Son of King John "Lackland" of England
Great x 4 Grandfather: William de Braose 4th Baron Bramber
Great x 3 Grandfather: Reginald de Braose 9th Baron Abergavenny
Great x 4 Grandmother: Maud "Lady of Hay" St Valery Baroness Bramber
Great x 2 Grandfather: William de Braose
Great x 3 Grandmother: Graecia Briwere
Great x 1 Grandmother: Maud de Braose
Great x 4 Grandfather: John Fitzgilbert
Great x 3 Grandfather: William Marshal 1st Earl Pembroke
Great x 4 Grandmother: Sybil of Salisbury
Great x 2 Grandmother: Eva Marshal
Great x 4 Grandfather: Richard "Strongbow" Clare 2nd Earl Pembroke
Great x 3 Grandmother: Isabel Clare Countess Pembroke
Great x 4 Grandmother: Aoife NI Diarmait Macmurrough Countess Pembroke and Buckingham
Father: Roger Mortimer 1st Earl March 3 x Great Grand Son of King John "Lackland" of England
Great x 4 Grandfather: Engeurrand "Crusader" Fiennes
Great x 3 Grandfather: William Fiennes
Great x 4 Grandmother: Sibylle Flanders
Great x 2 Grandfather: Enguerrand Ingleram Fiennes
Great x 4 Grandfather: Alberic Dammartin
Great x 3 Grandmother: Agnes Dammartin
Great x 4 Grandmother: Mathilde Clermont
Great x 1 Grandfather: William Fiennes
Great x 2 Grandmother: Isabel Provence
GrandMother: Margaret Fiennes 4 x Great Grand Daughter of King Henry "Curtmantle" II of England
Great x 4 Grandfather: Erard Brienne II Count Brienne
Great x 3 Grandfather: John de Brienne I King Jerusalem
Great x 4 Grandmother: Agnès Montfaucon Countess Brienne
Great x 2 Grandfather: John Beaumont 2 x Great Grand Son of King Henry "Curtmantle" II of England
Great x 4 Grandfather: Alfonso IX King Leon
Great x 3 Grandmother: Beregaria Ivrea Great Grand Daughter of King Henry "Curtmantle" II of England
Great x 4 Grandmother: Berengaria Ivrea I Queen Castile Grand Daughter of King Henry "Curtmantle" II of England
Great x 1 Grandmother: Blanche Beaumont 3 x Great Grand Daughter of King Henry "Curtmantle" II of England
Great x 4 Grandfather: Geoffrey Chateaudun V Viscount Châteaudun
Great x 3 Grandfather: Geoffrey Chateaudun VI Viscount Châteaudun
Great x 2 Grandmother: Jeanne Chateaudun
Great x 3 Grandmother: Clemence Roches Countess Blois
Agnes Mortimer Countess of Pembroke 4 x Great Grand Daughter of King John "Lackland" of England
Great x 3 Grandfather: Geoffrey IV de Joinville
Great x 2 Grandfather: Simon de Joinville
Great x 4 Grandfather: Guy Dampierre
Great x 3 Grandmother: Héluis aka Helvide Dampierre
Great x 4 Grandmother: Helvide Baudémont
Great x 1 Grandfather: Geoffrey Geneville 1st Baron Geneville
GrandFather: Piers Geneville
Great x 4 Grandfather: Hugh Lacy
Great x 3 Grandfather: Walter Lacy Lord Meath
Great x 4 Grandmother: Rohese Monmouth Baroness Lacy
Great x 2 Grandfather: Gilbert Lacy
Great x 4 Grandfather: William de Braose 4th Baron Bramber
Great x 3 Grandmother: Margaret de Braose
Great x 4 Grandmother: Maud "Lady of Hay" St Valery Baroness Bramber
Great x 1 Grandmother: Maud Lacy Baroness Geneville
Great x 4 Grandfather: Roger Bigod 2nd Earl Norfolk
Great x 3 Grandfather: Hugh Bigod 3rd Earl Norfolk
Great x 4 Grandmother: Ida Tosny Countess Norfolk
Great x 2 Grandmother: Isabel Bigod
Great x 4 Grandfather: William Marshal 1st Earl Pembroke
Great x 3 Grandmother: Maud Marshal Countess Norfolk and Surrey
Great x 4 Grandmother: Isabel Clare Countess Pembroke
Mother: Joan Geneville Baroness Mortimer 2nd Baroness Geneville 7 x Great Grand Daughter of King Henry I "Beauclerc" England
Great x 4 Grandfather: Hugh Lusignan IX Count Lusignan
Great x 3 Grandfather: Hugh Lusignan X Count Lusignan V Count La Marche
Great x 2 Grandfather: Hugh Lusignan XI Count Lusignan VI Count La Marche II Count Angoulême
Great x 4 Grandfather: Aymer Angoulême I Count Angoulême
Great x 3 Grandmother: Isabella of Angoulême Queen Consort England
Great x 4 Grandmother: Alice Courtenay Countess Angoulême
Great x 1 Grandfather: Hugh Lusignan XII Count Lusignan VII Count La Marche III Count Angoulême 5 x Great Grand Son of King Henry I "Beauclerc" England
Great x 4 Grandfather: Robert Capet II Count Dreux
Great x 3 Grandfather: Peter of Dreux aka Mauclerc Duke Brittany
Great x 4 Grandmother: Yolande Coucy Countess Dreux
Great x 2 Grandmother: Yolande Capet Countess Lusignan, La Marche and Angoulême 4 x Great Grand Daughter of King Henry I "Beauclerc" England
Great x 4 Grandfather: Guy Thouars
Great x 3 Grandmother: Alix Thouars Duchess of Brittany 3 x Great Grand Daughter of King Henry I "Beauclerc" England
Great x 4 Grandmother: Constance Penthièvre Duchess Brittany 2 x Great Grand Daughter of King Henry I "Beauclerc" England
GrandMother: Jeanne Lusignan 6 x Great Grand Daughter of King Henry I "Beauclerc" England
Great x 2 Grandfather: Raoul Fougères
Great x 1 Grandmother: Jeanne Fougères Countess Lusignan Countess La Marche and Angoulême