L. Frank Baum 
Rinkitink in Oz 

In L. Frank Baum’s "Rinkitink in Oz", (1916) Rinkitink, a plump jolly fellow, and his grouchy goat Bilbil assist Inga, the crown prince of Pingaree in reclaiming his lost kingdom from invaders. Inga is helped in his efforts by three magic pearls: one blue, giving him superhuman strength; one pink, protecting him from harm, and one white, providing words of wisdom. But when the pearls are lost, can Queen Ozma, watching events on her magic mirror save the day? The tenth in the Oz books series, it was adapted from an original non-Oz fantasy novel by Baum.