For 20 years, it has been under Ibara's reign of terror; he abuses the medusa device to petrify anyone who defies him in the slightest.
Later, after the Kingdom of Science exposes Ibara's crimes, the rightful heir Soyuz took his place as the kingdom's next ruler.
The kingdom was founded by the descendants of the astronauts who were the only known humans to not be petrified. 17 years prior to the start of the series, Ibara petrified Soyuz's father to claim the throne for himself. Ibara tried to kill Soyuz because the infant witnessed the assassination. However, Soyuz's mother took the child and fled the island with him.