POPE. Ugo Boncompagni, Gregory xiii (1502-1585) Pope in 1572, he instituted the Gregorian calendar. Handwritten bull in his name, Rome at St. Peter's nones de juillet (July 7) 1575, 4th year of his pontificate; vellum in-plano (57 x 73.5 cm), "Gregorius" in large letters with floral ornaments and ornate first line initials, lead seal Gregorius Papa XIII hanging on a hempen cord (2 pale wetnesses at the folds); in Latin. Bull with its seal, concerning Gaspard Gorin, priest of Rouen, and the premonstratensian monastery of Sainte-Marie de l'Île Dieu ("Insuladei") of Rouen. The Pope recalls the acts taken by his predecessors and by the King of France concerning this establishment... Chancellery signatures.