The Bourbon-Busset family is an illegitimate branch of the House of Bourbon, being thus agnatic descendants of the Capetian dynasty. Historically, they have been regarded as non-dynastic since decisions rendered by Louis XI of France. Possibly, however, the family may be canonically legitimate, in which case it is the most senior extant male-line branch of the Capetians, and senior to the Bourbons which reign today in Spain and Luxembourg and have in the past ruled France, Naples and Sicily, as well as to the House of Braganza, also Capetians by illegitimate descent. The head of the family uses the title of Count of Busset, which derives its name from the marriage of Pierre de Bourbon with Marguerite de Tourzel, heiress of the barony of Busset. Their son Philippe married Louise Borgia, Duchess of Valentinois, only legitimate child of Cesare Borgia, Duke of Valentinois.
Pierre de Bourbon, chamberlain of Louis XII of France; married in 1498 Marguerite de Tourzel d'Alègre, heiress to the barony of Busset; this alliance was the start of the House de Bourbon-Busset;
Although the marriage between Louis and Catherine took place before Louis was consecrated as a priest, which would have made it canonically impossible for him to marry, it was kept secret, being against the interests of Louis XI of France. French alliances in the Low Countries were not compatible with those of the House of Egmont. The French king therefore never recognized any children of the marriage as legitimate. There was a de facto legitimization of the Bourbon-Bussets when they were allowed the treatment of a Cousin du Roi. For the rest of history, the Bourbon-Bussets never claimed anything more than what they had, and constantly remained faithful servants of the Bourbon kings.
, daughter of the count of Lignières, is a great-great-granddaughter of Jacques, youngest son of the 8th Count of Busset, making her Jacques' fourth cousin once removed. She got married in 1927 with a royal Bourbon relative, Xavier, titular duke of Parma and Carlistpretender to the throne of Spain. Although Madeleine brought as dowry the , at the time this marriage was not accepted as dynastic by the titular duke, Xavier's elder brother, obtaining dynastic recognition retroactively around the time of the engagement of Xavier's eldest son to the daughter of Queen Juliana of the Netherlands in 1964. As the wife of Xavier, Madeleine was, however, proclaimed Queen consort of Spain by the remaining Carlists in 1952. Widowed in 1977, she remained a staunch adherent of her husband's Carlist principles. She excluded her elder son from the funeral of her husband as disloyal to his father's traditionalist Carlism, recognizing instead the claim to Carlist leadership and to Lignières of her younger son, Prince Sixtus Henry of Bourbon-Parma, Duke of Aranjuez, who continued the rivalry with his brother as Carlist pretender. A senior male-line descendant of the Bourbon-Bussets was the French writer Jacques de Bourbon-Busset, member of the French Academy. President Charles de Gaulle was once quoted telling him: Had it not been for the decision of King Louis XI, you might well be head of state of France today, instead of me. Since 2001, the head of the House of Bourbon-Busset is Charles de Bourbon, Count of Busset, who is a civil engineer of the Ecole des Mines de Paris, and Mayor of Ballancourt-sur-Essonne. He is the son of Jacques de Bourbon-Busset.
