Following Sarah's recent terrific guest post about Eleanor of Provence, queen of England, Edward II's paternal grandmother, I thought it was time for a post about his other grandmother Jeanne de Dammartin, known in English as Joan of Ponthieu, queen of Castile and Leon, countess of Ponthieu and Aumale in her own right.
Joan's date of birth is unknown but is estimated as around 1220 or perhaps a year or two earlier. At the time of her birth, Philip Augustus was still king of France, having reigned since 1180, while the young Henry III had recently succeeded his father John as king of England. Joan was in fact the great-niece of Philip Augustus, her maternal grandmother Alais/Alys/Alex (who lived until c. 1220) being the king's elder half-sister. Henry III of England would also loom large in Joan's life: she was betrothed to him for a few months in 1234/35, and in 1254 her daughter married his son. According to Dr John Carmi Parsons, biographer of Joan's daughter Eleanor of Castile, Joan was known to be a great beauty. 
Joan's father was Simon de Dammartin, count of Aumale, who was born around 1180 as the son of Aubry de Dammartin, count of Aumale, and Mathilde de Clermont, and was about forty when his eldest daughter was born. Simon opposed Philip Augustus and fought against him at the battle of Bouvines in 1214, despite already being married to his niece, Joan's mother Marie, who was born probably in April 1199. She was the only (surviving) child of the seemingly rather mismatched marriage between Guillaume Talvas, count of Ponthieu and Alais, daughter of Louis VII of France and Constance of Castile and older half-sister of Philip Augustus. Guillaume and Alais married in 1195 when they were sixteen and almost thirty-five respectively, shortly after Richard Lionheart, king of England, finally returned his repudiated fiancée Alais to France and her brother the king. Philip may have been hoping that Alais and Guillaume's marriage would remain childless and that the county of Ponthieu would thus fall to the French crown, but Marie survived, and although she did not at first inherit the county on her father's death in 1221 - Philip Augustus gave it to his cousin Robert, count of Dreux - she came to an agreement with his son Louis VIII in 1225. Count Simon died in 1239, Countess Marie in 1251.
Joan of Ponthieu had three younger sisters, Matilda (or Agatha), Philippa and Marie, all of whom lived long enough to marry. In England the inheritance of Ponthieu and Aumale would have been shared equally between the four sisters, but France practised primogeniture also for women, and thus Joan as the eldest sister inherited everything. She was therefore a rich matrimonial prize, and in 1234/35 Henry III of England cast his eye on her and sent envoys to Ponthieu asking for her hand. Marital negotiations advanced far enough that Henry wrote to Simon de Dammartin asking that Joan be sent to England before Pentecost, 27 May 1235, so that she might be crowned its queen on that day, and the two pledged themselves by verba de presenti, a binding agreement to marry.  Ponthieu, though neither large nor particularly rich, bordered Flanders and the duchy of Normandy, which Henry's father King John had lost to Philip Augustus in 1204. The county was thus strategically important and would have made an excellent base for an English campaign to regain Normandy. Philip Augustus's daughter-in-law Blanche of Castile and his grandson Louis IX were sufficiently alarmed at the prospect to threaten Simon de Dammartin and his daughter with invasion if the marriage to the king of England went ahead.
Henry III obligingly married instead Eleanor of Provence, whose elder sister Marguerite was already married to Louis IX, while Blanche of Castile, in collaboration with her eldest sister Queen Berenguela, arranged Joan's marriage to Berenguela's widowed son Fernando III of Castile and Leon, which had the dual benefit of allying the future countess of Ponthieu to the queen-regent of France's family and packing her off hundreds of miles out of the way. Joan and Fernando were second cousins once removed by common descent from Alfonso VII of Castile (Alfonso VII - Constanza of Castile - Alais of France - Marie of Ponthieu - Joan of Ponthieu; Alfonso VII - Fernando II of Leon - Alfonso IX of Leon - Fernando III), for which they required a papal dispensation to marry.
The exact date of Joan and Fernando's marriage is uncertain, but had taken place before the end of October 1237. Joan was probably about seventeen (though may have been twenty), Fernando twenty years older with eight children, seven sons and a daughter, still alive from his first marriage to Beatriz of Swabia (two other daughters had died in infancy). His eldest child Alfonso was close to Joan's own age, having been born in November 1221, and with six other sons as well the chances that a son of Joan's would accede to the Castilian throne were vanishingly small; one notable disadvantage of marrying Fernando rather than Henry III of England, who had no previous wife and no children. It probably goes without saying that we know next to nothing about Fernando and Joan's personal relationship and whether their marriage was a happy one; perhaps Joan was favourably impressed with her husband's military prowess, as town after town across Al-Andalus fell to him in the 1230s and 1240s. Córdoba had been captured the year before their wedding, Niebla and Huelva fell to Fernando the year after, Écija in 1240, and so on. In 1244 Fernando moved permanently to the south of Spain to better continue his operations against the Almohads, and Joan accompanied him, presumably with their young children, including Leonor, future queen of England. Joan and her children likely took part in the triumphal procession into Seville on 22 December 1248, which had fallen to Fernando following a sixteen-month siege a month earlier.
Joan and Fernando's eldest child, don Fernando, was born in 1238 or 1239. Their second, Edward II's mother doña Leonor, was probably born in late 1241, perhaps in Valladolid where Fernando III spent much of the winter of 1241/42, though it is not entirely clear if Joan was with him. A third child, don Luis, followed before the end of March 1243 (when he and Fernando's other children were named in the just-finished chronicle De Rebus Hispaniae Libris IX of don Rodrigo Jimenez de Rada, archbishop of Toledo and Fernando III's chancellor). Two other sons, Juan and Ximen - the latter named after Joan's father Simon de Dammartin - died young; Juan died shortly after birth some time after February 1244 and was buried in Córdoba, while Ximen was buried in Toledo, presumably before Fernando and Joan moved permanently south early that year. 
Joan was probably only in her early thirties when she was widowed on 30 May 1252. King Fernando III of Castile and Leon, the great warrior-king, died in the city of Seville which he had recaptured from the Almohads, the city of which he would be made patron saint centuries later. Queen Joan was at her husband's death-bed. According to the court historian Jofré de Loaysa, who was also present at Fernando's death, the king was buried on Saturday 1 June "in front of the altar of the Church of Santa María in Seville" and "in the presence of all his children except the archbishop of Toledo [don Sancho]."  This would of course include Edward II's then ten-year-old mother Leonor. Fernando was succeeded as king by Joan's thirty-year-old stepson Alfonso X, who was married to Violante of Aragon, fifteen-year-old daughter of Jaime I 'el Conquistador'. (She was also the elder sister of Isabel of Aragon, who married Philip III of France and was the paternal grandmother of Edward II's queen Isabella of France.)
According to Alfonso X's biographer, the new king was always very respectful to his stepmother, though perhaps their relationship was a rather distant and detached one. Fernando III had given his queen 'doña Juana' an extremely generous land settlement, including Córdoba, Carmona, Marchena, Luque and other estates and territories in the provinces of Córdoba, Jaén and Arjona. After Fernando's death Joan agreed with Alfonso X that she would keep only Marchena (I passed through this town on the train between Málaga and Seville on 30 May, incidentally).  Queen Joan returned to her native Ponthieu in or shortly after July 1254, when she and her eldest child don Fernando, then about fifteen, were granted a safe-conduct by Henry III of England to pass through his territory of Gascony. Fernando was called Fernando of Ponthieu, not of Castile, presumably on the grounds that he was heir to the county ("Ferrand de Pontibus, son of Ferdinand sometime king of Castile and Leon").  Perhaps Joan felt more comfortable living in her own lands, with her own language around her, than she did in a Castile ruled by her stepson, but of course I can only speculate. Her daughter Leonor married Lord Edward, son and heir of Joan's former fiancé Henry III of England, in Burgos on or around 1 November 1254 (see link above); her younger son don Luis, who was eleven or twelve in 1254, remained behind in Castile, and began to witness charters of his half-brother Alfonso X in October 1255.  Luis was eventually to marry a Castilian noblewoman, Juana Gómez de Manzanedo, lady of Gatón, with whom he had a son Luis and a daughter Berenguela, while don Fernando made an alliance both with France and England when he married the French noblewoman Laure de Montfort, niece of Henry III's brother-in-law Simon de Montfort, earl of Leicester. Luis died sometime before 1279; Fernando died in or before 1264, leaving a son, Jean de Ponthieu, who was killed at the battle of the Golden Spurs (aka the battle of Courtrai) on 11 July 1302.
Contemporary and possibly malicious and untrue rumour had it that Queen Joan took another of her stepsons, the colourful don Enrique, who was at least ten years her junior (born 1230), as her lover. As Alfonso X's biographer H. Salvador Martínez puts it: "Don Enrique, a rebellious, adventurous figure inclined to fall in love, was mocked by satirical poetry in the period that paint him as the lover of his stepmother, whose coif he would take into battle with him as a lucky charm. Other poems present Queen Juana crying and begging her husband for mercy for the prince." Martínez also states that after Fernando III's death, "The relations between the brothers worsened when Alfonso [X] found out that Enrique had become the lover of doña Juana of Ponthieu...for Alfonso had loved and honoured Fernando [III] and had promised him on his death-bed that he would protect his mother-in-law [sic]. Enrique's relations with doña Juana dishonoured the memory of Fernando III, so Alfonso took drastic measures against his brother."  Enrique fled from Castile in 1256 following a failed rebellion against Alfonso X and spent three years in England cheerfully sponging off his half-sister Leonor's father-in-law Henry III, having most probably passed through Ponthieu and spent time with Joan on the way. 
Probably at the beginning of the 1260s, Joan married her second husband, Jean de Nesle, lord of Falvy and La Hérelle, who I assume was one of her vassals. When her son-in-law Edward I of England and daughter Queen Eleanor were returning to England from the Holy Land in the summer of 1274, they stayed with Joan in Ponthieu, and left their two-year-old daughter, Joan's namesake Joan of Acre, with her. Granddaughter and grandmother remained together until Queen Joan's death. John Carmi Parsons has speculated that Joan of Acre had been "perhaps thoroughly spoiled by an indulgent grandmother."  Doting on her grandchildren is something Joan had in common with Eleanor of Provence, and makes me wish both women could have lived longer and been a presence in their grandson Edward of Caernarfon's life (he had Eleanor of Provence till he was seven, at least).
Joan, countess of Ponthieu and Aumale, dowager queen of Castile and Leon and mother of the queen of England, died on 16 March 1279, probably aged sixty or almost. Her widower Jean de Nesle lived until February 1292 (which would seem to indicate that he was younger than her). Queen Joan outlived all four of her sons Fernando, Luis, Juan and Ximen, and was survived by her daughter Eleanor, queen of England, and several grandchildren. Joan's grandson Jean de Ponthieu inherited her county of Aumale, while her county of Ponthieu passed to her daughter Queen Eleanor and in 1290 to her grandson Edward of Caernarfon.
1) John Carmi Parsons, Eleanor of Castile: Queen and Society in Thirteenth-Century England (1995), pp. 8-9.
2) Margaret Howell, Eleanor of Provence: Queenship in Thirteenth-Century England (1998), pp. 10-12.
3) All the information about the births and deaths of Joan and Fernando's children, and the approximate date of their wedding, comes from Parsons, Eleanor of Castile, pp. 8-9, 259-260 notes 9 to 11; Parsons, 'The Year of Eleanor of Castile's Birth and her Children by Edward I', Mediaeval Studies, 46 (1984), pp. 245 on. I am indebted to Dr Parsons for his superb research and scholarship.
4) H. Salvador Martínez, trans. by Odile Cisneros, Alfonso X, the Learned (2010), p. 97.
5) Ibid., pp. 41, 111, 112.
6) Calendar of Patent Rolls 1247-1258, pp. 311, 351.
7) Parsons, 'Year of Eleanor of Castile's Birth', p. 247.
8) Martínez, Alfonso X, p. 111 note 64, p. 305.
9) Parsons, Eleanor of Castile, pp. 18-20.
10) Ibid., pp. 31, 40.