I’ve recently been engrossed in Ana Mardoll’s deconstruction of the Chronicles of Narnia, which has so far reached Chapter 11 of Prince Caspian. One quite valid point she made is why it is considered so important that Narnia be ruled by humans, known in that world as Sons of Adam and Daughters of Eve. Mardoll writes, “In classic Christian mythology, God created the world in seven days, starting with light and water and land and plants, working his way up to animals, and then capping off his grand creation with the invention of humans. These humans are given dominion over the earth and the animals, because they are implied to be very different from the animals….But Narnia is a world where that humanness — language, intelligence, philosophy, free will, and the creation of legacies — is extended to every imaginable type of animal and hybrid….So why, I wonder, would a legacy reaching to Adam and Eve be any more important in this world than one reaching to Brenda and Brice, the first intelligent beavers, or Mickey and Minnie, the mice who first walked the earth and laughed in delight at its wonders?” Then again, do rules pertaining to who can be the monarch ever make that much sense when you think about them?
Although there are humanoid and part-human species in Narnia, actual humans are quite rare, and they’re all descended from foreigners. Indeed, Adam and Eve aren’t supposed to have existed in Narnia, yet everyone there seems to know about them. Exactly how this is so develops throughout the series, but in The Lion, the Witch, and the Wardrobe we’re basically presented with a country where humans are more or less mythical. It kind of seems like they aren’t even native to the world, but we’re told once the Pevensies take the thrones that “they entered into friendship and alliance with countries beyond the sea and paid them visits of state and received visits of state from them,” and that kings and princes sought to marry Susan and Lucy. It’s not specifically stated that the inhabitants of these other countries are human, but it’s likely. Maybe that’s why it’s so important that Narnia have a human ruler, as it might be easier for humans in other countries to deal with one of their own than a talking animal or nature spirit. That’s just a guess, though. In Prince Caspian, C.S. Lewis seems to hedge his bets by having Narnia conquered by humans, but humans specifically said to be descended from pirates who entered the Narnian world through a magic portal. When Caspian X comes along and romanticizes Old Narnia, the natives decide to throw in their lot with him.
It’s in The Magician’s Nephew that we’re finally told the source for all the other humans who show up with increasing frequency in later books. Two of the first people to arrive in Narnia are a London hansom cab driver named Frank and his wife Helen, who are appointed the first king and queen by Aslan. Hence, Frank and Helen essentially are the Adam and Eve of the Narnian world, but they themselves are a Son of Adam and Daughter of Eve. Their children mate with the local humanoid population, and their descendants eventually become more numerous and spread out into Archenland and Calormen. The latter grows into a great empire and world power, while Narnia seems to maintain a small human population mostly limited to the royal family. By the time of LWW, the humans all appear to be gone from the country, perhaps due to the efforts of the White Witch. So when the Pevensies return to England without leaving an heir, who rules in Narnia? Aslan makes a big deal about how there should be a Son of Adam or Daughter of Eve on the throne, then gets rid of the only humans with a claim to the throne(s). What’s up with that? The Telmarines don’t arrive until some centuries later, and we’re never filled in on the history that occurs in between these events. I suppose the end of Narnia’s permanent winter would lead to more immigration, and I do recall some humans being part of the Pevensies’ court in The Horse and His Boy. So there COULD have been other human monarchs in the meantime, but we don’t really know.