JOHN XV. (pope from 985 to 996) is now generally recognized as the successor of Boniface VII., the pope of the same name who was said to have ruled for four months after the murder of Boniface being now omitted by the best authorities. John XV. was the son of Leo, a presbyter in Gallina Alba. At the time he mounted the papal chair Crescentius was patrician of Rome, but, although his influence was on this account very much hampered, the presence of the empress Theophania in Rome from 989 to 991 restrained also the ambition of Crescentius. On her departure the pope, whose venality and nepotism had made him very unpopular with the citizens, found it necessary to flee to Tuscany. The news of the approach of Otho III. made it possible for him soon afterwards to return, but he died of fever before the arrival of Otho, who elevated his own kinsman Bruno to the papal dignity under the name of Gregory V.

JOHN XVI. (pope or antipope from 997 to 998) was a Calabrian Greek by birth, and a favourite of the empress Theophania, from whom he had received the bishopric of Placentia. His original name was Philagathus. In 995 he was sent by Otho III. on an embassy to Constantinople to negotiate a marriage with a Greek princess. On his way back he either accidentally or at the special request of Crescentius visited Rome. A little before this Gregory V., in the beginning of 997, had been compelled to flee from the city; and the wily and ambitious Greek had now no scruple in accepting the papal tiara from the hands of Crescentius, to whom he consented to give up the temporal authority on condition that he recognized his subordination to the Western empire. The arrival of Otho at Rome in the spring of 998 put a sudden end to the treacherous compact. John sought safety in flight, but was discovered in his place of hiding and brought back to Rome, where after enduring cruel and ignominious tortures he was immured in a dungeon.

JOHN XVII., whose original name was Sicco, succeeded Silvester II. as pope in June 1003, but died in less than five months afterwards.

JOHN XVIII. (pope from 1003 to 1009) was, during his whole pontificate, the mere creature of the patrician John Crescentius, and ultimately he abdicated and retired to a monastery, where he died shortly afterwards. His successor was Sergius IV.