One of the more obscure facts about Glinda is that she created the Forbidden Fountain with the Waters of Oblivion, at the center of Oz, whose waters redeemed a former King of Oz who was exceptionally cruel. This happened "many centuries ago" according to Ozma (again alluding to Glinda's advanced age), and it is this fountain that saves Oz from the invading Nome King and his allies in "The Emerald City of Oz", by making them forget their nefarious intentions. Glinda clearly made the Fountain at a point in Oz's history when the Land was unified under one of the members of the Royal Family of Oz, albeit a tyrannical king in this isolated incident, and so she was able to intervene in a way that she could not when the country was divided between the Wizard and the Wicked Witches of the East and West et al., prior to Dorothy's arrival.