The 500 Hats of Bartholomew Cubbins

Each time Bartholomew Cubbins attempts to obey the King's order to take off his hat, he finds there is another one on his head.
Set in feudal times, the story begins in the Kingdom of Didd, when King Derwin is riding through a street past Bartholomew Cubbins, a poor boy in the market. Bartholomew removes his hat, according to the laws, but another hat mysteriously appears; when he attempts to remove this one too, another one appears again, and this continues, even as he removes more and more hats, each growing in extravagance and beauty from the 451st hat onwards.