Henry the Fat (Basque: Henrike I.a, Gizena, French: Henri le Gros, Spanish: Enrique el Gordo) was King of Navarre (as Henry I) and Count of Champagne and Brie (as Henry III) from 1270 until his death.
Henry was the youngest son of Theobald I of Navarre and Margaret of Bourbon. During the reign of his childless older brother Theobald II he held the regency during many of Theobald's numerous absences. In 1269, Henry married Blanche of Artois, daughter of the then-reigning King Louis IX of France's brother Count Robert I of Artois. Recognized as heir presumptive during his brother's reign, Henry succeeded to the thrones of the Kingdom of Navarre and County of Champagne upon Theobald II's death in December 1270.
After Henry's death, his only legitimate child, a one-year-old daughter named Joan, succeeded him under the regency of her mother Blanche. Joan's 1284 marriage to Philip the Fair, the future King of France, in the same year united the crown of Navarre to that of France and saw Champagne devolve to the French royal domain.