Katherine, Duchess of Lancaster (born Katherine de Roet, c. 1349 – 10 May 1403) was the third wife of John of Gaunt, Duke of Lancaster, the fourth (but third surviving) son of King Edward III. From her earlier marriage, she is known as Katherine Swynford.
Daughter of a knight from Hainaut, Katherine, whose name is also spelled "Katharine" or "Catherine", was brought up at the English royal court, later found herself in the service of Blanche of Lancaster, the first wife of John of Gaunt. At that time, she was married to Hugh Swynford (or de Swynford), one of the Duke's knights. After the death of the Duchess, Katherine became the lady-in-waiting of her daughters, and also took care of them.
After the death of Hugh Swynford, she became a member of the household of the Duke's new wife, Constance of Castile, and she was given management of the estates of her deceased husband in Lincolnshire: Coleby and Kettlethorpe. She soon became the mistress of John of Gaunt. From this connection, at least four children were born, who received the surname Beaufort after one of their father's French estates. Those four children were later legitimized by the Church, as the result of their parents' eventual marriage.
In addition, Gaunt gave his mistress several estates, and also provided her with a generous allowance. Since the relationship between Katherine and John of Gaunt caused public condemnation, in 1381 the Duke was forced to break their relationship. Katherine then settled in a rented house in Lincoln.
Despite the formal break, Katherine's relationship with her former lover and the rest of his family continued to be quite cordial. In 1387, she was made a Lady of the Garter by King Richard II, and shortly thereafter she became a member of the household of Mary de Bohun, wife of Henry Bolingbroke, eldest son and heir of John of Gaunt, who later became King of England under the name of Henry IV.
In the early 1390s, the love affair between Katherine and John of Gaunt resumed, and after the death of his second wife, the Duke unexpectedly married his mistress in 1396, which caused discontent among the English nobility. However, in the same year, a papal bull was received, recognizing the marriage as valid, and all the children born from the connection were legitimised. After the death of the Duke in 1399, Katherine retired to her rented house in Lincoln, where she died four years later. She was buried at Lincoln Cathedral.
Katherine and John of Gaunt's descendants, the Beaufort family, played a major role in the Wars of the Roses. Henry VII, who became King of England in 1485, derived his claim to the throne from his mother, Margaret Beaufort, who was a great-granddaughter of Gaunt and Swynford. His legal claim to the throne, therefore, was through a cognatic and previously illegitimate line. Henry VII's first action was to declare himself king "by right of conquest" retroactively from 21 August 1485, the day before his army defeated King Richard III at the Battle of Bosworth.
Through her son, John Beaufort, 1st Earl of Somerset, and her daughter, Joan Beaufort, Countess of Westmorland, Katherine became the ancestor of all English (and later British) monarchs since Edward IV.
Katherine's father was Paon de Roet, a herald and, later, knight (who was "probably christened as Gilles"), who came to England in the entourage of Philippa of Hainaut, who married King Edward III. His origin is not documented. Payne's family nickname was Roe (French: Roët). On this basis, it has been suggested that he was related to the powerful family of the Lords of Le Roeulx, who owned a lordship in the County of Hainaut, whose name was spelled differently: Rouet, Roëlt, Ruet. The origin of this genus has been traced back to Charlemagne. Their possessions were mainly concentrated around the city of Le Rœulx, located 8 miles northeast of Mons. They also included the towns of Roux (located 40 miles east of Mons) and Faurœulx (20 miles south). However, according to the historian Alison Weir, there is reason to doubt this version of Paon's origin: the chronicler Jean Froissart, who himself was from Hainaut, was most likely well aware of his origin, but does not write anything about his nobility. As Paon's father, he points to a certain Jean de Roët (died 1305), son of Huon de Roët. Froissart gives no titles for any of them. At the same time, Weir notes that this version cannot be completely discarded: Paon de Roet could indeed come from a younger line of the Le Roeulx family, since the spelling of the generic names Roeulx and Roët are quite similar and they could well be interchangeable. In addition, the name Gilles, which Paon received at baptism, was quite common in the family of the Lords of Le Roeulx.
Additional evidence of the possible relationship of Paon de Roet with the Lords of Le Roeulx is the heraldic similarity of the coats of arms of Paon and the Le Roeulx family. The coat of arms of the city of Le Rœulx is a golden lion on a green field with a wheel in its paw, which is a play on words: in French, roue means wheel. The same theme was adopted by Paon's family: the coat of arms of his daughter, Katherine Swynford, was three gold wheels on a red field, however, judging by the heraldic emblems on the vestments given to her by Lincoln Cathedral, on her coat of arms until 1396, when she married John of Gaunt, there were three simple silver wheels; she probably inherited this coat of arms from her father.
Based on the description of his epitaph, Paon was King of Arms of Aquitaine for a time. In England, he was in the service of Queen Philippa. After the outbreak of the Hundred Years' War in 1340, he took part in the early stages of the English army, including fighting at the Battle of Crécy and the siege of Calais. Not later than 1349, Paon returned to Hainaut, where he served Countess Margaret II of Hainaut, sister of Queen Philippa.
There is no reliable information regarding Katherine's mother. According to some reports, Paon de Roet was married twice. It has been suggested that one of his wives was a relative of Queen Philippa, but there is no documentary evidence for this version. Alison Weir believes that two children were born from Paon's first wife: the eldest daughter, Isabel (also called Elizabeth) —who later became in the Noble canoness of the very influential Saint Waltrude Collegiate Church in Mons (which, according to Weir, is evidence of Paon's close connection with the ruling family of Hainaut)—, and a son, Walter. The mother of Katherine and another daughter, Philippa (who married the famous English poet Geoffrey Chaucer), was, according to Weir, Paon's second wife.
Katherine's year of birth is not documented. In 1631, John Weever claimed that she was the eldest of Paon de Roet's daughters, but that would make her at least 28 years old at the time of her first marriage, which is much older than the typical age girls married. Alison Weir believes that Weever did not know about the existence of Elizabeth de Roet and the other two daughters. The author of the article of Katherine Swynford in the Oxford Dictionary of National Biography believes that she was born around 1350, with which Weir agrees. They calculate the possible year of her birth based on the fact that Katherine married for the first time around 1362/1363 and gave birth to her first child around 1363/1364, and the canonical age at which a girl could marry and have marital relations with her husband, in that time was 12 years old. Weir further clarifies that Katherine was most likely born in 1349. She was probably named after St. Catherine of Alexandria whose cult at that time was gaining strength.
Katherine's birthplace is sometimes called Picardy, with which Alison Weir does not agree. This error, in her opinion, arises from the fact that some historians confuse Philippa de Roet, Katherine's sister, who was in the service of Queen Philippa, with certain Philippa Picard, but these are completely different personalities. Katherine was probably born in the County of Hainaut, as indicated by the account of the chronicler Jean Froissart, who calls her a "resident" from there, and the chronicler Henry Knighton, who calls her "a certain foreigner". It is possible that Katherine's birthplace was her father's possessions, located near Mons.