In 'The 500 Hats of Bartholomew Cubbins', what is the name of the king?

In “The 500 Hats of Bartholomew Cubbins,” the king is King Derwin. His fuller name is King Theobald Thindner Derwin, the ruler of the Kingdom of Didd.

King Derwin encounters Bartholomew after the boy removes his hat but mysteriously continues to wear another one. Because the kingdom’s law requires people to uncover their heads before the king, Derwin treats the endless hats as a serious offense and brings Bartholomew to the palace.

The king’s attempts to solve the problem become increasingly elaborate, ending with a threatened execution and then a plan to throw Bartholomew from a tower. When the hats become more beautiful as they are removed, Derwin changes course and buys all 500 for 500 gold coins. Derwin later reappears in “Bartholomew and the Oobleck,” so he is not King Nool or King Yertle.