. . and Whitsun ("White Sunday") is so called because either (sources vary) it was the last day that the newly baptised of Easter wore their white robes of baptism to mark the end of the Easter season, or because they dragged them out again for that same reason, - not therefore because the Morris dancers were wearing white for the first time in the year (although I suppose nothing says that either tradition predates the other - or that they both don't derive from something earlier still.)