The underground realm of Agarttha was first introduced to the Western world in 1886 by the French esoteric philosopher Alexandre Saint-Yves d'Alveydre with his book Mission de l'Inde, translated here for the first time into English. Saint-Yves' book maintained that deep below the Himalayas were enormous underground cities, which were under the rule of a sovereign pontiff known as the Brahatma. Throughout history, the "unknown superiors" cited by secret societies were believed to be emissaries from this realm who had moved underground at the onset of the Kali-Yuga, the Iron Age.