Biography of Isabella of Castile Duchess York 1355-1392
Paternal Family Tree: Ivrea
Maternal Family Tree: María González Henestrosa Lady Villagera 1356
In 1355 Isabella of Castile Duchess York was born illegitimately to Peter "Cruel" I King Castile (age 20) and Maria Padilla (age 21).
On 03 Apr 1367 the forces of [her father] Peter "Cruel" I King Castile (age 32) commanded by Edward "Black Prince" (age 36) defeated the army of [her uncle] Henry "Fratricide" II King Castile (age 33) at the Battle of Nájera at Nájera [Map]. The English forces included John of Gaunt 1st Duke Lancaster (age 27), William Scrope, Peter Courtenay (age 21), John Devereux 1st Baron Devereux (age 30), John Savile of Shelley and Golcar (age 42), Bernard Brocas (age 37) and Thomas Banastre (age 33).
The forces of Henry "Fratricide" II King Castile included Bertrand Geusclin (age 47). The battle achieved little since Bertrand Geusclin escaped.
John Ferrers 4th Baron Ferrers of Chartley (age 36) was killed. His son Robert Ferrers 5th Baron Ferrers of Chartley (age 9) succeeded 5th Baron Ferrers of Chartley. Margaret Despencer Baroness Ferrers of Chartley by marriage Baroness Ferrers of Chartley.
Edward "Black Prince" thereafter returned home, taking Peter's daughters [her illegitimate sister] Constance (age 13) and Isabella (age 12) as hostages to ensure Peter would pay the money owed to Edward. Constance married John of Gaunt 1st Duke Lancaster, Isabella married Edmund of Langley 1st Duke of York (age 25).
After 21 Sep 1371 Isabella of Castile Duchess York (age 16) accompanied her sister [her illegitimate sister] Constance of Castile Duchess of Lancaster (age 17) to England after her marriage to John of Gaunt 1st Duke Lancaster (age 31).
On 11 Jul 1372 Edmund of Langley 1st Duke of York (age 31) and Isabella of Castile Duchess York (age 17) were married at Wallingford, Oxfordshire [Map]. She by marriage Countess Cambridge. She being the younger sister of Constance (age 18) who had married Edmund's older brother John of Gaunt 1st Duke Lancaster (age 32) a year before. An example of Marriage of Two Sets of Siblings. She the illegitmate daughter of Peter "Cruel" I King Castile and Maria Padilla. He the son of King Edward III of England (age 59) and Philippa of Hainault Queen Consort England.
Around 1373 [her son] Edward 2nd Duke of York 1st Duke Albemarle was born to Edmund of Langley 1st Duke of York (age 31) and Isabella of Castile Duchess York (age 18) at King's Langley, Hertfordshire [Map]. He a grandson of King Edward III of England.
Around 1374 [her daughter] Constance York Countess Gloucester was born to Edmund of Langley 1st Duke of York (age 32) and Isabella of Castile Duchess York (age 19) at Conisbrough Castle [Map]. She a granddaughter of King Edward III of England.
Before 07 Nov 1379 [her son-in-law] Thomas Despencer 1st Earl Gloucester (age 6) and [her daughter] Constance York Countess Gloucester (age 5) were married. She the daughter of Edmund of Langley 1st Duke of York (age 38) and Isabella of Castile Duchess York (age 24). They were third cousin once removed. He a great x 3 grandson of King Edward I of England. She a granddaughter of King Edward III of England.
In 1381 [her son] Edward 2nd Duke of York 1st Duke Albemarle (age 8) and [her daughter-in-law] Beatrice Burgundy Countess Rutland and Cork (age 8) were married. She the daughter of Ferdinand I King Portugal (age 35) and Leonor Teles Meneses Queen Consort Portugal. He the son of Edmund of Langley 1st Duke of York (age 39) and Isabella of Castile Duchess York (age 26). They were second cousin once removed. He a grandson of King Edward III of England.
Before 1385 John Holland 1st Duke Exeter (age 32) was rumoured to be having an affair with Isabella of Castile Duchess York (age 29) wife of Edmund of Langley 1st Duke of York (age 43).
On 20 Jul 1385 [her son] Richard of Conisbrough 1st Earl Cambridge was born to Edmund of Langley 1st Duke of York (age 44) and Isabella of Castile Duchess York (age 30) at Conisbrough Castle [Map] although there was speculation the father was John Holland 1st Duke Exeter (age 33) with whom Isabella of Castile Duchess York was suspected of having an affair. He a grandson of King Edward III of England.
On 06 Aug 1385 Edmund of Langley 1st Duke of York (age 44) was created 1st Duke York by King Richard II of England (age 18). Isabella of Castile Duchess York (age 30) by marriage Duchess York.
Thomas of Woodstock 1st Duke of Gloucester (age 30) was created 1st Duke Albemarle, and around the same time, 1st Duke Gloucester. Eleanor Bohun Duchess Gloucester (age 19) by marriage Duchess Albemarle and Duchess Gloucester.
On 23 Dec 1392 Isabella of Castile Duchess York (age 37) died. She the wife of Edmund of Langley 1st Duke of York (age 51). Isabella had travelled to England with her sister [her illegitimate sister] Constance of Castile Duchess of Lancaster (age 38) who had married Edmund's elder brother John of Gaunt 1st Duke Lancaster (age 52). Isabella and Edmund's marriage was not, apparently, a happy one. She is known to have had an affair with John Holland 1st Duke Exeter (age 40) who may have been the father of [her son] Richard of Conisbrough 1st Earl Cambridge (age 7) progenitor of the House of York.
On 13 Jan 1393 Isabella of Castile Duchess York was buried at King's Langley Priory, Hertfordshire [Map].
Kings Wessex: Great x 11 Grand Daughter of King Edmund "Ironside" I of England
Kings England: Great x 6 Grand Daughter of King Henry "Curtmantle" II of England
Kings Scotland: Great x 10 Grand Daughter of King Duncan I of Scotland
Kings Franks: Great x 17 Grand Daughter of Louis "Pious" King Aquitaine I King Franks
Kings France: Great x 10 Grand Daughter of Robert "Pious" II King France
Anne Neville Queen Consort England
Brigadier-General Charles FitzClarence
Great x 4 Grandfather: Ferdinand III King Castile III King Leon Great Grand Son of King Henry "Curtmantle" II of England
Great x 3 Grandfather: Alfonso X King Castile X King Leon 2 x Great Grand Son of King Henry "Curtmantle" II of England
Great x 4 Grandmother: Elisabeth Hohenstaufen Queen Consort Castile Queen Consort Leon 
Great x 2 Grandfather: Sancho IV King Castile IV King Leon 3 x Great Grand Son of King Henry "Curtmantle" II of England
Great x 4 Grandfather: James I King Aragon 
Great x 3 Grandmother: Violante Barcelona Queen Consort Castile Queen Consort Leon
Great x 4 Grandmother: Violant Árpád Queen Consort Aragon
Great x 1 Grandfather: Ferdinand IV King Castile IV King Leon 4 x Great Grand Son of King Henry "Curtmantle" II of England
Great x 2 Grandmother: Maria Molina Queen Consort Castile Queen Consort Leon
GrandFather: Alfonso "Avenger" XI King Castile 4 x Great Grand Son of King Henry "Curtmantle" II of England
Great x 4 Grandfather: Alfonso "Fat" II King Portugal 
Great x 3 Grandfather: Alfonso III King Portugal Great Grand Son of King Henry "Curtmantle" II of England
Great x 4 Grandmother: Urraca Ivrea Queen Consort Portugal Grand Daughter of King Henry "Curtmantle" II of England
Great x 2 Grandfather: Denis I King Portugal 2 x Great Grand Son of King Henry "Curtmantle" II of England
Great x 4 Grandfather: Alfonso X King Castile X King Leon 2 x Great Grand Son of King Henry "Curtmantle" II of England
Great x 3 Grandmother: Beatrice Queen Consort Portugal 3 x Great Grand Daughter of King Henry "Curtmantle" II of England
Great x 4 Grandmother: Mayor Guillén de Guzmán
Great x 1 Grandmother: Constance Burgundy Queen Consort Castile Queen Consort Leon 3 x Great Grand Daughter of King Henry "Curtmantle" II of England
Great x 4 Grandfather: James I King Aragon
Great x 3 Grandfather: Peter III King Aragon
Great x 4 Grandmother: Violant Árpád Queen Consort Aragon
Great x 2 Grandmother: Elisabeth Barcelona Queen Consort Portugal 6 x Great Grand Daughter of King William "Conqueror" I of England
Great x 4 Grandfather: Manfred King Sicily
Great x 3 Grandmother: Constance Hohenstaufen Queen Consort Aragon 5 x Great Grand Daughter of King William "Conqueror" I of England
Great x 4 Grandmother: Beatrice Savoy Marchioness of Saluzzo 4 x Great Grand Daughter of King William "Conqueror" I of England
Father: Peter "Cruel" I King Castile 5 x Great Grand Son of King Henry "Curtmantle" II of England
Great x 4 Grandfather: Alfonso "Fat" II King Portugal
Great x 3 Grandfather: Alfonso III King Portugal Great Grand Son of King Henry "Curtmantle" II of England
Great x 4 Grandmother: Urraca Ivrea Queen Consort Portugal Grand Daughter of King Henry "Curtmantle" II of England
Great x 2 Grandfather: Denis I King Portugal 2 x Great Grand Son of King Henry "Curtmantle" II of England
Great x 4 Grandfather: Alfonso X King Castile X King Leon 2 x Great Grand Son of King Henry "Curtmantle" II of England
Great x 3 Grandmother: Beatrice Queen Consort Portugal 3 x Great Grand Daughter of King Henry "Curtmantle" II of England
Great x 4 Grandmother: Mayor Guillén de Guzmán
Great x 1 Grandfather: Alfonso "Brave" IV King Portugal 3 x Great Grand Son of King Henry "Curtmantle" II of England
Great x 4 Grandfather: James I King Aragon
Great x 3 Grandfather: Peter III King Aragon
Great x 4 Grandmother: Violant Árpád Queen Consort Aragon
Great x 2 Grandmother: Elisabeth Barcelona Queen Consort Portugal 6 x Great Grand Daughter of King William "Conqueror" I of England
Great x 4 Grandfather: Manfred King Sicily
Great x 3 Grandmother: Constance Hohenstaufen Queen Consort Aragon 5 x Great Grand Daughter of King William "Conqueror" I of England
Great x 4 Grandmother: Beatrice Savoy Marchioness of Saluzzo 4 x Great Grand Daughter of King William "Conqueror" I of England
GrandMother: Maria Burgundy Queen Consort Castile 4 x Great Grand Daughter of King Henry "Curtmantle" II of England
Great x 4 Grandfather: Ferdinand III King Castile III King Leon Great Grand Son of King Henry "Curtmantle" II of England
Great x 3 Grandfather: Alfonso X King Castile X King Leon 2 x Great Grand Son of King Henry "Curtmantle" II of England
Great x 4 Grandmother: Elisabeth Hohenstaufen Queen Consort Castile Queen Consort Leon
Great x 2 Grandfather: Sancho IV King Castile IV King Leon 3 x Great Grand Son of King Henry "Curtmantle" II of England
Great x 4 Grandfather: James I King Aragon
Great x 3 Grandmother: Violante Barcelona Queen Consort Castile Queen Consort Leon
Great x 4 Grandmother: Violant Árpád Queen Consort Aragon
Great x 1 Grandmother: Beatrice Ivrea Queen Consort Portugal 4 x Great Grand Daughter of King Henry "Curtmantle" II of England
Great x 2 Grandmother: Maria Molina Queen Consort Castile Queen Consort Leon
Isabella of Castile Duchess York 6 x Great Grand Daughter of King Henry "Curtmantle" II of England
Great x 1 Grandfather: Garcia Padilla
GrandFather: Juan García Padilla 1st Lord Villagera
Mother: Maria Padilla
Great x 1 Grandfather: Fernán González Henestrosa
GrandMother: María González Henestrosa Lady Villagera