Pope John XVII
John XVII, né Sicco (died November 6, 1003), succeeded Silvester II as pope in June 1003, but died less than five months afterwards.
The previous legitimate Pope John was John XV. "John XVI" was an anti-Pope, and his regnal number XVI should have been reused. But this did not occur, and the sequencing has never been corrected. Also, since there was never a Pope John XX at all, this means there have only been 21 legitimate popes named John, not 23 as the regnal number of Pope John XXIII would suggest.
This article incorporates text from the public domain 1911 Encyclopædia Britannica.
