There have been some interesting debates about whether Hild is really a fantasy novel rather than a straight historical novel. Many have said, with justification, that even if there is no actual magic in the book, it still has the flavor and attack of a work of fantasy. Genre border arguments are ultimately pointless except to advertisers and marketers, and I don't wish to add to the misguided shouting. But I think a lot of discussions have overlooked the possibility of examining Hild not as fantasy, but as science fiction.
I realize, of course, that there are as many competing guidelines to differentiate fantasy from science fiction as there are critics, and that, again, these differentiations mostly don't matter. (They don't ultimately matter to me either; I'm skeptical of genre boundaries, as I've said publicly -- indeed, I said it on the panel I shared with Nicola.) But as an intellectual exercise this interests me, because I think it's easy to be distracted by the medeival setting and think that fantasy or history are our only choices.
For purposes of this essay I'm going to use the differentiating rule I devised a few years ago for a paper on the subject. If you don't like this set of definitions, you probably won't agree with the essay. To me:
A work of science fiction assumes that all that needs to be known can, eventually, be known through the application of human senses, human reason, and such devices as we can contrive. By contrast, a work of fantasy assumes that there are some important things which are not fully comprehensible by human means, no matter how advanced or sophisticated we get; some things are ineffable.
This is why Star Trek, despite its handwaving, and Doctor Who, despite its handfluttering, are science fiction to me rather than fantasy -- because their waved or fluttered aspects are still assumed to be things that can be understood, if we just get smarter brains and better equipment in a few hundred or a few thousand years. But the Harry Potter books, despite their technicality, have important topics that are marked as being essentially insoluble mysteries. What differentiates science fiction from mainstream fiction, in this regard, is that either it takes place at a time when our ability to comprehend the world and act on it has resulted in changes in that world, or else the process of knowing and understanding the world through our senses and our reason are integral to the story itself.
It is in this latter regard that I think of Hild as a work of science fiction. Its eponymous protagonist is taken by her contemporaries to be a seer, to have magical access to things going on beyond her immediate knowledge, and even to predict the future. This she appears to accomplish through omens, dreams, and visions. Because her delicate political position, her physical safety, and the safety of her friends and family depend on maintaining that role, she plays it as well as she can.
But the reader knows, as Hild herself knows, that she has no such magical abilities. She is, instead, a keenly sensitive observer of every detail of the world around her, from the condition of the feathers on a bird's wing and the overtones in the flavor of a cup of mead to the quirks and idiosyncracies of those she meets, as well as having a firm and unsentimental grasp of the economic and political realities of her time and place. She also possesses a ferocious intelligence, which gives her the ability to take the many details she absorbs and to build patterns from them that allow her to make shrewd probabalistic estimates of what is happening many miles away or what will happen soon. Thus her conclusions strike everyone around her as magical, because no other person is able to arrive at them so quickly or so accurately. In this, she resembles no other character in fiction so much as Sherlock Holmes.
Thus, Hild is about how a person navigates the world when she is so observant and intelligent that she can comprehend things far beyond the ken of those on whom her safety depends. The process of observation and induction (what Holmes erroneously called deduction) is central to the action of the novel, and is recounted deliciously in Hild's subjective impressions. Science fiction, which glories in the accomplishments of the mind, has many protagonists like this. Most immediately to my mind comes Bean, the central character in Orson Scott Card's Shadow novels, but I'm sure you could come up with a dozen yourself. Indeed, it is one of our familiar tropes (unsurprising in that many readers of science ficiton imagine themselves to be intellectually superior to those around them, and frustrated to tears at their inability to make the dullards understand).
It would be a horrible disservise to the novel to claim that Hild's abilities as an encyclopedic genius are the only interesting things about it. It is a wonderful work of character, relationship, and hard choices, and the most immersive work about the middle ages I've ever read. But I wanted to make this claim about SF because, as I say, I think it's been overlooked. Hild is a science fiction hero.