The Nuttall Encyclopedia
The eve of the 1st May, when the witches hold high revel and offer sacrifices to the devil their chief, the scene of their festival in Germany being the Brocken (q. v .). This annual festival was in the popular belief conceded to them in recompense for the loss they sustained when by St. Walpurga the Saxons were persuaded to renounce paganism with its rites for Christianity.
Wood, James, ed. Entry for 'Walpurgis Night'. The Nuttall Encyclopedia. https://www.studylight.org/encyclopedias/eng/nut/w/walpurgis-night.html. Frederick Warne & Co Ltd. London. 1900.