One of the three Satanic high holidays (along with All Hallows' Eve and the practitioner's birthday). The holiday takes place on April 30th. Walpurgisnacht is named for an 8th century saint from Sussex whose remains now lie in Eichstadt. According to the Anton LaVey's Church of Satan, all the powers of evil manifest on earth on the Eve of May to hold wild revels and celebrate the spring equinox.