Edward II was at least the fourteenth and perhaps the sixteenth child of Edward I, who was almost forty-five at the time of his son's birth on 25 April 1284, and his first queen Eleanor of Castile, who was about forty-two and a half at the time. Edward was their youngest child; his supposed younger sisters Beatrice and Blanche, who are even today sometimes still added to the long list of Edward and Eleanor's children, are inventions of much later writers. Only six of Eleanor of Castile's children outlived her: Edward II; Eleanor, countess of Bar; Joan of Acre, countess of Gloucester; Margaret, duchess of Brabant; Mary, a nun; Elizabeth, countess of Holland and Hereford. Edward II's three elder brothers all died young; they were John (July 1266 - August 1271), Henry (May 1268 - October 1274) and Alfonso (November 1273 - August 1284). Edward I also had two sons by his second wife Marguerite of France who survived into adulthood, Thomas, earl of Norfolk (1300-1338) and Edmund, earl of Kent (1301-1330). Edward II's grandparents were: Henry III, king of England (d. 1272); Eleanor of Provence, queen of England (d. 1291); Fernando III, king of Castile and Leon (d. 1252); Jeanne de Dammartin, queen of Castile and countess of Ponthieu in her own right (d. 1279). For more about his ancestors, see here and here.
Isabella's parents were Philippe IV, king of France (1268 - 29 November 1314) and Jeanne, queen of Navarre and countess of Brie and Champagne in her own right (January 1273 - late March/early April 1305). Isabella's grandparents were: Philippe III, king of France (d. 1285); Isabel of Aragon, queen of France (d. 1271); Enrique or Henri I, king of Navarre (d. 1274); Blanche of Artois, queen of Navarre and countess of Lancaster (d. 1302). Isabella and Edward II both lost their mothers at a young age, Edward six, Isabella about nine. Marguerite of France, in addition to being Edward II's stepmother, was Isabella's aunt, Philippe IV's younger half-sister, while Isabella's grandmother Blanche of Artois was also Edward II's aunt by marriage. By blood, however, Edward and Isabella were not particularly closely related, at least not by the inbred standards of later European royal families, being second cousins once removed: Edward's grandmother Eleanor of Provence was the younger sister of Isabella's great-grandmother Marguerite, queen of Louis IX. (Louis, incidentally, was seventy years to the day older than Edward II, being born on 25 April 1214.) Their son Edward III and his queen Philippa of Hainault were second cousins, both great-grandchildren of Philippe III of France and Isabel of Aragon (Philippe III - Philippe IV - Isabella - Edward III; Philippe III - Charles, count of Valois - Jeanne de Valois - Philippa).
Isabella - who was presumably named after her paternal grandmother Isabel of Aragon - was the sixth of seven siblings, who were all born very close together in time. Only the date of the eldest brother, Louis X, is known: 4 October 1289, when their father was twenty-one and their mother sixteen. The next two sons were also kings of France: Philippe V, born probably between 1291 and 1293, and Charles IV, apparently born in 1294. The youngest child, Robert, was born in 1297, and died in August 1308 at the age of about eleven. Isabella was born most probably in the second half of 1295 or at the beginning of 1296, so was around eleven and a half years younger than her husband. She also had two older sisters, Marguerite and Blanche, who died in or shortly after 1294 and are very obscure, only really known from a betrothal to Fernando IV of Castile arranged by their father in 1294. If either sister had lived, it's possible that she would have married Edward II instead of Isabella. One of the two sisters may have been older than Louis X and born in 1288, though the date can't really be pushed back any further than that because of Queen Jeanne's youth (born in 1273), or perhaps both girls were born sometime between 1290 and 1293, between Philippe V and Charles IV. Were any of the siblings multiple births? I have no idea, but seven children were born between 1288/89 and 1297, and if they were all single births, Queen Jeanne must have been almost perpetually pregnant.
Isabella was the only one of Philippe IV's seven offspring who had sons who lived past childhood, Edward III (1312-1377) and John of Eltham, earl of Cornwall (1316-1336). Louis X, Philippe V and Charles IV fathered five sons between them who died young. They were: King Jean I 'the Posthumous' of France, son of Louis and Clemence of Hungary, 15 November - 20 November 1316; Philippe (January 1313 - March 1321) and Louis (June 1316 to January 1317), sons of Philippe V and Jeanne of Burgundy; Philippe (January 1314 - March 1322), son of Charles IV and his first wife Blanche of Burgundy; and Louis, born and died March 1324, son of Charles IV and his second wife Marie of Luxembourg. The three brothers also had nine daughters between them, but as women could not inherit the throne of France, it passed, on the death of Charles IV in 1328, to his first cousin Philippe VI, the first Valois king of France, son of Philippe IV's brother Charles, count of Valois (1270-1325). Louis X's daughter, however, inherited the kingdom of Navarre, to which the Valois had no claim, and became Queen Jeanne II. The last of the Capets, the dynasty which had ruled France since 987, were Philippe V's daughter Marguerite, countess of Burgundy, Artois, Flanders, Nevers and Rethel (d. 9 May 1382), and Charles IV's daughter Blanche, duchess of Orléans (d. 8 February 1382). In 1314, Philippe IV must have assumed that the future of his dynasty was assured; he had three sons aged between twenty and twenty-five, all of them married, all of them already fathers. He could hardly have guessed that a mere fourteen years later they would all be dead without surviving male issue and that his brother's descendants would rule in France in their place - or that his daughter's son Edward III of England some years later would claim the throne and begin the Hundred Years War.
I looked once at some distant ancestors of Edward II (see link above), and here are some of Isabella's:
- Isabella was the great-great-great-great-great-great-great-granddaughter of Harold Godwinson, the king of England killed at Hastings in 1066. Harold's daughter Gytha married, probably in the early 1070s or thereabouts, Vladimir Monomakh, grand prince of Kiev, and I can't be the only person fascinated as to how and why that marriage came about - that there was a connection between England and distant Kiev in the eleventh century. Gytha and Vladimir had five sons together, the eldest, Mstislav, being Isabella's ancestor via his daughter Euphrosyne, who married King Geza II of Hungary. Isabella's paternal grandmother Isabel of Aragon was the daughter of Yolande or Violante of Hungary, daughter of King Andras II. And so, with Edward III, the blood of Harold Godwinson returned to the English royal family.
- Via her maternal grandmother Blanche of Artois, queen of Navarre and countess of Lancaster, Isabella was the great-great-great-great-granddaughter of Isaac Angelos, emperor of Byzantium (d. 1204) and of the Holy Roman Emperor Friedrich Barbarossa (d. 1190).
- Via both her parents, Isabella was the great-great-great-great-granddaughter of Henry II and Eleanor of Aquitaine, both lines descended from Henry and Eleanor's second daughter Eleanor, queen of Castile and her daughter Blanche of Castile, queen of France.
- Isabella was, via their daughter Agnes, the great-great-great-great-granddaughter of Raynald de Châtillon, prince of Antioch (a character in the film Kingdom of Heaven and quite a few novels) and his wife Constance, who had previously been married to Eleanor of Aquitaine's uncle Raymond of Poitiers. Raynald and Constance's daughter married Bela III of Hungary (son of Geza II and Euphrosyne of Kiev, mentioned above) and was the mother of Andras II. Bela III married secondly, without issue, Marguerite, daughter of Louis VII of France and Constance of Castile, and widow of Henry the Young King.
To end the post, here are some of Edward II's first cousins:
Sancho IV, king of Castile
Beatriz, queen of Portugal
Margaret, queen of Norway
Arthur, duke of Brittany
Eleanor, abbess of Fontevrault
Marie, countess of St Pol
Beatriz, marchioness of Montferrat
Violante, lady of Biscay
Martin, abbot of Valladolid
Juan Manuel, duke of Peñafiel, one of the greatest medieval Spanish writers
Jean, count of Aumale
And some of Isabella of France's first cousins:
Catherine, titular empress of Constantinople, queen of Albania and princess of Achaea
Philippe VI, king of France
Isabelle, duchess of Brittany
Edward II's half-brothers Thomas of Brotherton, earl of Norfolk and Edmund of Woodstock, earl of Kent
Henry of Grosmont, first duke of Lancaster
Jeanne, countess of Hainault and Holland
Jeanne, countess of Artois
Isabelle, abbess of Fontevrault