“In Gondor the New Year will always now begin upon the twenty-fifth of March when Sauron fell, and when you were brought out of the fire to the King.”
Gandalf, The Return of the King
“For centuries theologians and leaders of the church had affirmed that the key date in human history was March 25, on which date occurred the Fall itself; the angel Gabriel’s Annunciation to Mary, which heralded the birth of the One who would undo the effects of the Fall; and the Crucifixion, which defeated the forces of evil, which had been unleashed on this world by Adam’s sin. It was with these events that Dionysus Exiguus, the sixth-century monk and calendar-maker, determined that the year itself should begin on March 25, which it did throughout Europe for a very long time. It was England’s official New Year’s Day until 1752, though by that time January 1 had been celebrated by most English people for hundreds of years.”
Alan Jacobs, Original Sin, p 43.