Today is the last day of winter in the old Gaelic year. Tomorrow, Beltane, will see the advent of the light, and the banishment of the darkness of winter for another half-year. In six months' time, Hallowe'en (All Hallows' Eve) will signal the end of summer, as we remember on 1 November those that have gone on ahead.
In continental Europe, the night of April 30th into May 1st is Walpurgisnight, which serves the same purpose. The town of Zutphen, 20 miles north of Arnhem in Holland, has a church dedicated to St Walpurgis.
In more recent history, April 30th, 1945, was the day that Adolf Hitler committed suicide towards the end of the Second World War. An evil spirit was certainly exorcised at that time.