Once you know Sauron was overthrown on the Feast of the Annunciation, many things become clear.
From Giants With Feet of Clay: On the Historiography of the Year 1000 by Dr. Richard Landes, Center for Millennial Studies:
"Why then, would a conservative Parisian cleric invoke the Eschaton in the year 1000? Understandably, someone in Rudolf of Fulda's day might do so, since then it was over a century and a half away -- but why someone with only a generation to go? The answer comes in the next incident Abbo reports: the apocalyptic rumor from Lotharingia which, he claimed, had 'filled almost the entire world.' This computus-based calculation predicted the End when the Passion and the Annunciation coincided on Friday, March 25, the very date of the creation of Adam, of the Annunciation, and of the Passion."
March 25 may be the most uncanny day in the calendar. Readers of The Lord of the Rings will recall that it is the day Sauron is overthrown, and which is therefore made New Year's Day. Once again, Tolkien was being creatively unoriginal: March 25 was sometimes New Year's Day in the Middle Ages. It is also the traditional date on which Doomsday is expected to occur.
This is my gift to the world's greeting-card companies.