Commentary Par XIX 137-138

  The uncle, barba, of Frederick II of Sicily was James, king of Majorca (and of Minorca).  He lost his crown for ten years as a result of joining Philip the Bold of France in a disastrous invasion of Catalonia.  His brother, James of Aragon (see [Purg VII 119]), in 1291 succeeded to the throne of Aragon, surrendering his kingship of Sicily, which his father had acquired, and appointed his younger brother, Frederick, to it in 1296.  By these acts the James boys dishonored both family and their kingship.