Saint Walpurga or Walburga, also spelled Valderburg or Guibor, was an Anglo-Saxon missionary to the Frankish Empire. She was canonized on 1 May c. 870 by Pope Adrian II. Saint Walpurgis Night is the name for the eve of her feast day in the Medieval period, which coincided with May Day; her feast is no longer celebrated on that day, but the name is still used for May Eve.