Papal elections in the Middle Ages were chaotic, often marked by violence and the influence of powerful Roman families and political rulers, leading to both legitimate popes and antipopes.
And thereafter Stephen put Pope Formosus out of his tomb, and placed him in the Apostolic throne, and a deacon was delegated to answer for him, and his apostolic vestment was stripped off, and dragged across the basilica; and blood was flowing from his mouth, and he was thrown into the river.