Rosemary and Darroll Pardoe, authors of "The Female Pope: The Mystery of Pope Joan", theorize that if a female pope did exist, a more plausible time frame is 1086 and 1108, when there were several antipopes; during this time the reign of the legitimate popes Victor III, Urban II, and Paschal II was not always established in Rome, since the city was occupied by Henry IV, Holy Roman Emperor, and later sacked by the Normans. This also agrees with the earliest known version of the legend, by Jean de Mailly, as he places the story in the year 1099. De Mailly's account was acknowledged by his companion Stephen of Bourbon.