Corona's monarchy is divided into a kingdom of king and queen. Currently, there are only two monarchs reigning over Corona. This being King Frederic and Queen Arianna. The latter had birth to Rapunzel, the heir to the throne, and her husband, Eugene Fitzherbert, who is the deemed prince of Corona.
History in Monarchy
The first ruler of Corona, Robin XI had changed the location and whereabouts of Corona, and had ultimately built Corona Castle.
After that, Robin had given birth to Herz Der Soone, in which the latter gave birth to King Frederic, who had Rapunzel, as the heir to the throne.