"May
29th is Royal Oak or Oak Apple Day. It was a public holiday in the UK
for nearly 200yrs until 1859. The birthday of Charles II, and conceived
of as a celebration of the restoration of the monarchy, its form was
inspired by an episode when the young Charles hid from the soldiers of
Oliver Cromwell in an oak tree. All manner of archaic elements readily
attached themselves to the holiday as can be seen in Castleton in the
present day in one of the few remaining acknowledgements of the date."