[64], 1388 [i.e. 1380] pp. Printed in two columns with shoulder notes and gloss; title-page printed in red and black; printer's device on title page; full-page woodcut family tree {Arbor Constnguinitatis). (4to) 25x17.5 cm (9¾x6¾"), period vellum with inked spine title.

Pope Gregory IX ( c. 1145/70 – 22 August 1241), was the head of the Catholic Church from 19 March 1227 to his death in 1241. He is known for instituting the Papal Inquisition, a mechanism that severely punished people accused of heresy, in response to the failures of the episcopal inquisitions established during the time of Pope Lucius III. Pp. 700-701 repeated with no duplication of text; pagination skips from 878 to 889 with no loss of text. The listing in OCLC/WorldCat (locating seven examples only) notes an engraved portrait with caption: Gregorius XIII PM, not present in this copy, but the family tree is not noted.