A Night of Diabolical Influences
"Everything that comes into the world calls forth a Luciferic and an Ahrimanic counterpart. The event which—as experienced by the Ingaevones—was part of the regular, ordained evolution of mankind was connected with the time of the first full moon after the vernal equinox. But owing to the precession of the equinox, what had remained from olden days as a dream-experience was transferred to a later date and therefore became Ahrimanic. When the experience that had arisen in ancient times in the true Hertha cult was advanced about four weeks, it became Ahrimanic. This meant that the union of the woman with the spiritual world was sought in an irregular way—at the wrong time. Here lies the explanation of the institution of the Walpurgis Night—between the 30th April and the 1st May. It is nothing but an Ahrimanic transposition of time. Luciferic transposition of time goes backward; Ahrimanic transposition of time runs in the opposite direction, being connected with the precession of the equinox. Thus the Ahrimanic, Mephistophelean form of the Hertha cult, the perversion into the diabolic, later became the Walpurgis Night; it is connected with the most ancient Mysteries of which only faint echoes remained."
Rudolf Steiner, The Festivals and Their Meaning I: Christmas, Lecture IV. Christmas at a Time of Grievous Destiny, GA 246, 21 December 1916, Basel.