Question: What is the cause of death of Joan Of England (1335–1348)'s mother?

Knowledge 1: Joan of England (1335–1348)
Joan of England (December 19, 1333 or January 28, 1334 – July 1, 1348) was a daughter of Edward III and his wife, Philippa of Hainault.Joan, also known as Joanna, was born on either December 19, 1333 or January 28, 1334 in the Tower of London.As a child she was placed in the care of Marie de St Pol, wife of Aymer de Valence and foundress of Pembroke College, Cambridge.She grew up together with her sister Isabella, her brother Edward, and their cousin Joan of Kent.Joan died in the Black Death that struck Europe in 1348. [SEP] Knowledge 2: Philippa of Hainault
Philippa of Hainault (Middle French: "Philippe de Hainaut"; 24 June c.1310/15 – 15 August 1369) was Queen of England as the wife of King Edward III.Edward promised in 1326 to marry her within the following two years.She was married to Edward, first by proxy, when Edward dispatched the Bishop of Coventry "to marry her in his name" in Valenciennes (second city in importance of the county of Hainaut) in October 1327.The marriage was celebrated formally in York Minster on 24 January 1328, some months after Edward's accession to the throne of England.In August 1328, he also fixed his wife's dower.Philippa acted as regent in 1346, when her husband was away from his kingdom, and she often accompanied him on his expeditions to Scotland, France, and Flanders.Philippa won much popularity with the English people for her kindness and compassion, which were demonstrated in 1347 when she successfully persuaded King Edward to spare the lives of the Burghers of Calais.This popularity helped maintain peace in England throughout Edward's long reign.The eldest of her thirteen children was Edward, the Black Prince, who became a renowned military leader.Philippa died at the age of fifty-six from an illness closely related to edema.The Queen's College, Oxford was founded in her honour.
Knowledge 1: Joan of England (1335–1348)
Joan of England (December 19, 1333 or January 28, 1334 – July 1, 1348) was a daughter of Edward III and his wife, Philippa of Hainault.Joan, also known as Joanna, was born on either December 19, 1333 or January 28, 1334 in the Tower of London.As a child she was placed in the care of Marie de St Pol, wife of Aymer de Valence and foundress of Pembroke College, Cambridge.She grew up together with her sister Isabella, her brother Edward, and their cousin Joan of Kent.Joan died in the Black Death that struck Europe in 1348. [SEP] Knowledge 2: Ælfthryth, wife of Edgar
Ælfthryth (– 1000 or 1001, also Alfrida, Elfrida or Elfthryth) was an English queen, the second or third wife of King Edgar of England.Ælfthryth was the first king's wife known to have been crowned and anointed as Queen of the Kingdom of England.Mother of King Æthelred the Unready, she was a powerful political figure.She was possibly linked to the murder of her stepson King Edward the Martyr and appeared as a stereotypical bad queen and evil stepmother in many medieval histories.
Knowledge 1: Philippa of Hainault
Philippa of Hainault (Middle French: "Philippe de Hainaut"; 24 June c.1310/15 – 15 August 1369) was Queen of England as the wife of King Edward III.Edward promised in 1326 to marry her within the following two years.She was married to Edward, first by proxy, when Edward dispatched the Bishop of Coventry "to marry her in his name" in Valenciennes (second city in importance of the county of Hainaut) in October 1327.The marriage was celebrated formally in York Minster on 24 January 1328, some months after Edward's accession to the throne of England.In August 1328, he also fixed his wife's dower.Philippa acted as regent in 1346, when her husband was away from his kingdom, and she often accompanied him on his expeditions to Scotland, France, and Flanders.Philippa won much popularity with the English people for her kindness and compassion, which were demonstrated in 1347 when she successfully persuaded King Edward to spare the lives of the Burghers of Calais.This popularity helped maintain peace in England throughout Edward's long reign.The eldest of her thirteen children was Edward, the Black Prince, who became a renowned military leader.Philippa died at the age of fifty-six from an illness closely related to edema.The Queen's College, Oxford was founded in her honour. [SEP] Knowledge 2: Ælfthryth, wife of Edgar
Ælfthryth (– 1000 or 1001, also Alfrida, Elfrida or Elfthryth) was an English queen, the second or third wife of King Edgar of England.Ælfthryth was the first king's wife known to have been crowned and anointed as Queen of the Kingdom of England.Mother of King Æthelred the Unready, she was a powerful political figure.She was possibly linked to the murder of her stepson King Edward the Martyr and appeared as a stereotypical bad queen and evil stepmother in many medieval histories.

Answer: edema