GREGORY V., pope from 996 to 999, a great-grandson of the emperor Otto the Great. Until the council of Pavia (997) his rival was the anti-pope John XVI., whom the people of Rome, in revolt against the will of the youthful emperor Otto III., had chosen after having expelled Gregory. The most memorable acts of his pontificate were those arising out of the contumacy of the French king, Robert, who submitted after a sentence of excommunication. Gregory died suddenly, and not without suspicion of foul play, on Feb. 18, 999. Twenty-two of his bulls are in Migne's Patrol Lat., vol.