Sir Henry Rider Haggard (1856-1925) was the originator, and is still one of the masters of what is known today as the "lost race novel," in which an intrepid adventurer discovers a lost people or city. Haggard's first such novel was the fantasy masterpiece SHE. Heart of the World is also a kind of fantasy, though not in the Tolkien sense, all the characters being very human. First out in 1895, it is a tragic story of love and betrayal in the lost Golden City of the Mayas and involves a secret society of Indians, the chief of whom is the heir to the last emperor of the Aztecs.
I have greatly enjoyed other Haggard books, and this one did not disappoint me.