by Susan Flantzer
© Unofficial Royalty 2022

Katherine Swynford was the long-time mistress and the third wife of John of Gaunt, 1st Duke of Lancaster, the fourth but the third surviving son of King Edward III of England and Philippa of Hainault. The descendants of Katherine Swynford and John of Gaunt are significant in English and Scottish history. The Tudor dynasty was directly descended from their eldest son John Beaufort, great-grandfather of King Henry VII of England, the first monarch of the House of Tudor. Katherine and John are the great grandparents of King Edward IV and King Richard III from the House of York. Their granddaughter Joan Beaufort married James I, King of Scots, and was an ancestor of the Scots House of Stuart and the English House of Stuart.

Born Katherine de Roet in circa 1350, probably in the County of Hainault, now part of Belgium and France, she was the daughter of Paon de Roet, a knight from Hainault who first came to England in 1328 when Philippa of Hainault married King Edward III of England. Katherine’s mother is unknown. Katherine’s father Paon de Roet remained in the service of Queen Philippa in England. He took part in the Hundred Years’ War, including at the Battle of Crécy and the Siege of Calais. In 1349, Paon de Roet returned to Hainault, where he served Margaret II, Countess of Hainault, Queen Philippa’s sister. In 1351, Paon de Roet accompanied Margaret II, Countess of Hainault, when she was forced to flee to England due to a civil war with her son. Paon de Roet returned to the County of Hainault in March 1352 but shortly thereafter, all mention of him disappears.

Katherine had three known siblings:

• Isabel de Roet (circa 1335/1336 – circa 1368), a nun and later canoness at the convent of Saint Waltrude Collegiate Church in Mons, County of Hainault, now in Belgium
• Walter de Roet (before 1338/1340 – circa 1356)
• Philippa de Roet (circa 1346 – circa 1387), married Geoffrey Chaucer, poet, author, and civil servant, author of The Canterbury Tales, had four children

From 1352, Katherine and her sister Philippa were raised in the household of Queen Philippa, wife of King Edward III of England. This would suggest that their mother was dead. Being raised in the household of the Queen of England, Katherine would have known all the members of the royal family including her future lover and husband John of Gaunt and would have been well versed in court etiquette and protocol. Queen Philippa would have ensured that Katherine received a good education.

Around 1360, Queen Philippa placed Katherine in the household of her daughter-in-law Blanche of Lancaster who was married to John of Gaunt. Blanche gave birth to seven children between 1360 and 1368, and Katherine assisted with their care. Around 1366, a marriage was arranged for Katherine by John of Gaunt at the request of his wife Blanche of Lancaster. Katherine married Sir Hugh Swynford (circa 1340 – 1371), a knight in service to John of Gaunt.

Katherine and Hugh had three children:

• Blanche Swynford (1367 – circa 1374), named for Blanche, Duchess of Lancaster, died in childhood
• Sir Thomas Swynford (1368 – 1432), married (1) Jane Crophill, had three children (2) Margaret Grey, no children
• Margaret Swynford (born c. 1369), became a nun at Barking Abbey in 1377 with help from her future stepfather John of Gaunt, where she lived the religious life with her cousin Elizabeth Chaucer, daughter of Geoffrey Chaucer and Katherine’s sister Philippa de Roet

On September 12, 1368, John of Gaunt’s wife Blanche of Lancaster died at age 23, possibly of the plague or possibly from childbirth complications, while John was away at sea. John married again on September 21, 1371, to Infanta Constance of Castile, the daughter of Pedro I, King of Castile and León. John and Constance had two children, a son who died in infancy and a daughter Catherine of Lancaster who married King Enrique III of Castile and León. Through his daughter Catherine, John of Gaunt is the great-grandfather of Isabella I, Queen of Castile and the great-great-grandfather of Catherine of Aragon (daughter of Isabella I of Castile and Ferdinand II of Aragon), the first wife of King Henry VIII of England. John of Gaunt is the ancestor of all subsequent monarchs of the Kingdom of Castile and a united Kingdom of Spain.

Three years after the death of Blanche of Lancaster, Katherine also lost her spouse. In 1370, Hugh Swynford went on a military campaign with John of Gaunt to Aquitaine in present-day France. When John of Gaunt returned to England in the fall of 1371, Hugh did not accompany him due to illness. He died in Aquitaine on November 13, 1371. His widow Katherine was given the management of Hugh’s estates in Coleby and Kettlethorpe in Lincolnshire, England.

After the death of her husband, Katherine became a member of the household of John of Gaunt’s second wife Constance of Castile. It is uncertain exactly when Katherine Swynford and John of Gaunt became lovers. However, the affair certainly had started by late 1372 as Katherine and John’s eldest child was born no later than 1373.

Katherine Swynford and John of Gaunt had had three sons and one daughter. Their children’s surname is derived from the name of the now-demolished Beaufort Castle, a property in Champagne, France that John of Gaunt had sold years before. John of Gaunt likely felt it was a safe name to give to his illegitimate children by Katherine Swynford.

• John Beaufort, 1st Earl of Somerset (circa 1373 – 1410), married Margaret Holland, had at least six children
• Henry, Cardinal Beaufort, Bishop of Winchester (circa 1375 – 1447), unmarried
• Thomas Beaufort, Duke of Exeter (circa 1377–1426), married Margaret Neville of Horneby, one son who died young
• Joan Beaufort, Countess of Westmorland (circa 1379–1440), married (1) Robert Ferrers, 5th Baron Boteler of Wem, had two daughters (2) Ralph de Neville, 1st Earl of Westmorland, had fourteen children

John gave Katherine several estates and a generous allowance. In 1381, John was forced to break off his relationship with Katherine out of political necessity. The 1371 marriage of John to his second wife Constance of Castile, a claimant to the throne of Castile, had been a calculated plan for England to gain control of the Kingdom of Castile, and John’s relationship with Katherine while being married to Constance was not helping in the plan to gain control of Castile. Constance of Castile died on March 24, 1394, and the English never gained control of the Kingdom of Castile.

In the early 1390s, even before the death of his wife Constance, John of Gaunt resumed his affair with Katherine. Two years after the death of his second wife Constance of Castile, John married Katherine on January 13, 1396, at Lincoln Cathedral in England. After the marriage of Katherine and John, their four children were legitimized by both John’s nephew King Richard II of England and Pope Boniface IX. After Henry Bolingbroke, John’s eldest son by his first wife Blanche of Lancaster, deposed his first cousin King Richard II in 1399, the new King Henry IV inserted the phrase excepta regali dignitate (“except royal status”) in the documents that had legitimized his Beaufort half-siblings and supposedly that phrase barred them from the throne. However, many disputed and still dispute the authority of a monarch to alter an existing parliamentary statute on his or her own authority, without the further approval of Parliament.

The descendants of Katherine Swynford and John of Gaunt are significant in English and Scottish history. The Tudor dynasty was directly descended from their eldest son John Beaufort, 1st Earl of Somerset, great-grandfather of King Henry VII of England. Henry VII based his claim to the English throne on the descent of his mother Lady Margaret Beaufort from John of Gaunt, a son of King Edward III. John Beaufort’s daughter Joan Beaufort married James I, King of Scots, and was an ancestor of the Scots House of Stuart and the English House of Stuart.

Katherine and John’s only daughter, another Joan Beaufort, was the maternal grandmother of two English kings from the House of York, the brothers King Edward IV and King Richard III. Henry Tudor defeated King Richard III at the Battle of Bosworth Field, becoming by conquest King Henry VII of England. Henry VII’s claim to the English throne was strengthened by marrying Elizabeth of York, the eldest daughter of King Edward IV and the great-granddaughter of Joan Beaufort, Katherine and John’s daughter.

John of Gaunt died on February 3, 1399, at Leicester Castle in England at the age of 58. Even though he had married two more times, John was buried with his first wife Blanche of Lancaster at Old St. Paul’s Cathedral in London. Unfortunately, the Great Fire of 1666 destroyed Old St. Paul’s Cathedral and the magnificent tomb of Blanche and John. Katherine Swynford, John’s widow, survived him by four years, dying in Lincoln, England, on May 10, 1403, at about the age of 53. She was buried at Lincoln Cathedral in Lincoln, England.

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Works Cited

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