http://mentalfloss.com/article/32001/10-other-doomsday-predictions-were-not-correct

Doomsday

1. 1284. When the Pope decrees something, people tend to listen. And they did, in 1213, when Pope Innocent III wrote that “the end of this beast is approaching, whose number, according to the Revelation of Saint John, will end in 666 years, of which already nearly 600 have passed."