Jean de Montaigu

Jean de Montaigu (1363 – 17 October 1409) was an advisor to Charles V and Charles VI of France.

His mother was Biette de Cassinel or Biota Cassinelli (c. 1340 – around 1380), called la belle Italienne ("the beautiful Italian woman"). She was the daughter of François Cassinel (died 1360), a sergeant in the Royal Army, and great-granddaughter of Bettino Cassinelli, who had immigrated from Italy to Paris. Although he was rumored to be an illegitimate son of Charles V of France, his father was actually Gerard de Montaigu, himself most like the bastard son of a non-noble family. The rumor arose from an erroneous translation into French of a comment made by Nicolas de Baye, the civil cleark of the Paris Parlement in 1409. The translation of Baye's original remark, that Gerard was the son "of a certain canon of Paris, so people said," left out the words "of a certain canon of Paris," causing the sentence to read "Gerart de Montagu, at the time of his death, and shortly before, knight, and previously notary of the king, and son, so people said." John of Montaigu's mother was Biette de Cassinel,

Biette Cassinel's brother Ferry Cassinel was bishop of Lodève in 1375, later bishop of Auxerre, and eventually Archbishop of Rheims.

Jean had two brothers or half-brothers: Gérard de Montaigu the Younger (died 1420), who was bishop of Poitiers and bishop of Paris; and Jean de Montaigu (died 1415), who was bishop of Chartres, and archbishop of Sens.

He made a career at the royal court, rising to become Charles VI's primary Master of the Household.

In 1409, duke John the Fearless of Burgundy arrested him, together with other "malefactors and false traitors". Montaigu was beheaded on 17 October 1409 in front of a large crowd in Paris, at the Gibbet of Montfaucon.