England 1345, and Sir Roger de Tourneville has volunteered to help King Edward III in his war against the French. A village contingent of the English army, fully prepped on the eve of leaving, crushes a small alien invasion force, by dint of cunning, superior numbers, and having no EMP-susceptible equipment or depletable bullets/explosives/laser charges — but plenty of reusable arrows, swords, sheer brute strength and a sense of righteous Christian indignation.
Using the captured spaceship and the grudging assistance of Branithar, a surviving alien interpreter (taught Latin by a local cleric), they launch a counter-invasion of the evil intergalactic empire, whom they view as the more prolific, Heaven-soiling brethren of the infidels overrunning the Holy Land. Because the invaders to our world have been dominant for so long over such a wide area, nobody up in the stars has any damn idea what politics are any more. Sir Roger, a man who's managed to survive medieval European politics quite well for some time, knows exactly what politics are, and manages to convince every single alien he meets, through bravado, underhandedness, trickery, and good old-fashioned lying, to assail their opponents. The only downside to their situation is that unfortunately the humans — not being astrogators, among other reasons — have no idea where Earth is any more.
The High Crusade provides examples of:
- Alien Invasion: Abortive, because the aliens land in exactly the wrong place.
- Alternate History Wank: Played straight and in time taken to Biblical proportions, despite the fact that this isn't actually an alternate history.
- Artistic License History: Parvus is portrayed as astonished when Branithat says the Earth is round, though he's aware of the idea from the ancient Greeks, and thinks it's absurd at first. However, that was actually well known by educated Medieval people (monks like him being at the forefront of education). Poul Anderson usually got history correct (from what was known then) but apparently didn't know flat earth belief in the Middle Ages is a myth (among the educated people at least).
- Battle Couple: Sir Roger and Lady Catherine. Also a Ruling Couple.
- Badass Israeli: The first humans they meet on their recontact with Earth hundreds of years later is a starfaring Israeli Empire.
- Boarding Party: The humans convince their alien allies to try this, because it was a standard naval technique at the time.
- Curbstomp Battle: Aliens vs. a Medieval army, it's a complete slaughter... for the aliens. Especially with the humans having superior numbers, and having no EMP-susceptible equipment and the aliens have no concept of hand-to-hand combat.
- Ironically inflicted on the invading Wersgorix. As it turns out, expecting to win just by virtue of having advanced weapons is a fool's errand when you're incapable of defending yourself.
- Deconstruction: It deconstructs the typical Alien Invasion story. While the medieval society the aliens find themselves in is technologically backward and with a very different value system from them, the people are not fearful cowards, but intelligent and resourceful souls who can fight them like any other enemy.
- Deliberate Values Dissonance: A captured alien is horrified that his captors consider it perfectly acceptable to have him stretched on the rack, and talks immediately, as much from disgust over such savagery as fear.
- Democracy Is Bad: Subverted in that while the Wersgorix notion of "democracy" is shown as a sham, the Jair republic proves itself to be a far better example of one.
- Disneyfication: A film version, produced by Roland Emmerich, was made in 1994. It takes the humorous-but-played-straight premise of the book and tries very hard to turn it into Monty Python and the Holy Grail... IN SPACE!! Sadly, this does not work particularly well.
- Easily Thwarted Alien Invasion: Despite the Wersgorix having millennia of technological progress on the humans and the element of surprise, they get defeated by the natives with downright embarrassing ease — the humans even manage to steal their ship and conquer them right back!
- Epic Fail: The Wersgorix invasion of Earth: their technologically advanced spaceship armed with laser weapons taking on a medieval village completely by surprise manages to not just get overrun, but captured and commandeered by said medieval villagers. Their mistake is assuming that the humans will panic and flee, when they happen to have landed in the middle of a small but well-prepared medieval army whose response is "fight" rather than "flight".
- Even Evil Has Standards: The Wersgorix see nothing wrong with imperialism and genocide, but are appalled at the medievals' use of Jack Bauer Interrogation Technique.
- Exact Words:
- Sir Roger is very good at bluffing while not actually, precisely lying."Our lords have extensive foreign possessions, such as Ulster, Leinster, Normandy — but I'll not weary you with a catalogue of planets." I alone noticed he had not actually said those counties and duchies were planets.
- Brother Parvus does it rather nicely, too, backing up Sir Roger's claim that Earthpeople have been exploring space for quite some time by mentioning that our first such endeavor was "about thirty-five hundred years [ago], at a place called Babel." Well, yes, a tower intended to reach into Heaven could be considered space exploration....
- Sir Roger is very good at bluffing while not actually, precisely lying.
- Fantastic Religious Weirdness:
"I presume you had a haunch of beef to break your fast," I said. "Are you sure it is not Friday? ... When is it Sunday?" I cried. "Will you tell me the date of Advent? How shall we observe Lent and Easter, with two moons morris-dancing about to confuse the issue?"
- Since the protagonists are transplanted Medieval English Catholics, they must adopt their religion somewhat after colonizing far-off planets and ruling other species that are new to them. For instance, there's debate over whether having sex with a female of another species is bestiality per the Biblical law. They also convert members of other species, with some even becoming bishops, and have their own "Popelet", while making clear this is merely a stand-in for the real Pope, whom they still owe allegiance to. Plus they have difficulty in regards to keeping religious holidays:
- This being a cheerful(ly whacked) work, they quote Jesus's words that the Sabbath was made for men and not the other way around, cheer up, and decide that they'll work it out.
- Feudal Future: Played straight and justified: the human newcomers offered a viable and stable socio-political system as well as centuries of experience at it whereas the Wersgorix mirrored the Western Roman Empire at its downfall and had long since forgotten how to actually conduct politics. Curiously though, even centuries later in the future, when Earth-bound humanity finally had spaceships of their own the interstellar empire forged by the crusaders and their descendants is very noticeably English.
- Framing Device: Twice. The story is framed as a chronicle written by a monk, framed in turn as a translation by a group encountering the descendants of the subjects of the story.
- Galactic Conqueror: Sir Roger, who manages to take over a huge galactic empire despite having been born a Medieval human knight.
- Good Republic, Evil Empire Inverted — the theoretical freedom of the Wersgorix "democracy" is unfavorably contrasted with the securities of the feudal system. Also played with, in that the Wersgor republic is also unfavorably contrasted with the Jair Republic (one of the lesser starfaring powers Sir Roger convinces to join his crusade against the Wersgor), with the Jair republic being described as a true republic, "not a sham one such as the Wersgor had", and the descriptions of the Wersgorix explicitly describing their state as all-powerful and the citizens as reflexively subservient to it and to their superiors. The Wersgorix are criticized for being too dependent on their Vast Bureaucracy and habitually subservient, similar criticisms to those levied against modern Western states by many conservatives.
- Humanity Is Superior: Well, it has a useful advantage or two.
- Humans Are Warriors: The ones the aliens pick on, anyway.
- I Made Copies: One that backfires, as two people separately destroy their only means of getting back to Earth in the belief that there's another copy in existence.
- Knight in Shining Armor: Played with. The humans are led by literal knights in shining armor, but they're pragmatic leaders and politicians.
- Lizard Folk: The Wersgorix are reptilian aliens who have blue skin.
- Medieval Morons: Subverted — and how! The morons end up conquering a space-faring empire.
- Nice Job Fixing It, Villain!: The humans plan to use the spacecraft to carry them en masse the Holy Land, but Branithar engages the autopilot to take them to the nearest Wersgorix colony where he assumes they'll be easy meat. They end up conquering the entire Wersgorix empire.
- Nicknaming the Enemy: "Bluefaces", for Wersgorix, because of their skin color.
- No Indoor Voice: Part of how Sir Roger outsmarts the first set of aliens he encounters. Their species does not have as sensitive hearing as the humans and therefore both does not realize that the humans are whispering to each other, but also don't realize that their own whispered planning is clearly audible.
- Outgrown Such Silly Superstitions: The Wersgorix. The humans on the other hand are very pious. While there is some tongue-in-cheek humor about Medieval practices and obsessions, their faith is definitely not portrayed as a bad thing, and the most humane character in the book by far is the narrator — who is a pious monk.
- Ramming Always Works: The English crash land their first captured warship, the Crusade, on an energy shielded Wersgorix battle fortress, crushing it. Then pissed off cavalry trample down the survivors.
- Rising Empire: One funded by good honest Englishmen by dint of skillful politics, force of personality, and lying where it's needed.
- Rock Beats Laser: Not to mention rock helps laser. A trebuchet firing nuclear shells? Undetectable by space age sensors? Yes please. At least once the people using the trebuchet are caught in the blast and killed. It worked on the base because the aliens were looking for an incoming missile with radar, and didn't see the lobbed trebuchet shot coming out of a patch of forest until it was already within exploding radius. They were ready for an incoming missile, and ready for humans trying to smuggle a bomb in on foot. They were completely unprepared for humans to carry the bomb on foot, then lob it the last thousand yards."That word sword. Do you mean a cutting weapon?"
I had no time to ask my master's advice. I prayed inwardly for steadiness and answered, "Yes. You have observed them on our persons in camp. We find them the best tool for hand-to-hand combat. Ask any survivor of the Ganturath garrison."
- Torture Technician: One-eyed Hubert. Who is quite pleased when Sir Roger threatens to apply the Jack Bauer Interrogation Technique on the captive Wersgorix. One-eyed Hubert also laments that Sir Roger isn't as quick with the irons as his grandfather, old Rip-Talon, and is quite dismayed to learn that he won't be getting to torture the Wersgor officer after all... right before he goes back to helping his little granddaughter gather daisies.
- The Upper Crass: The hero of the novel, Sir Roger de Tourneville is a baron of a small town in northern Lincolnshire. His lands being poor and backward, and his few periods away being spent fighting, he is acknowledged by even his friends as lacking in "courtly graces" being a blunt, jovial, bombastic and at times crude man. But is nevertheless a shrewd and highly cunning individual, as well as a great military leader. This is particular highlighted compared to his wife Lady Catherine, daughter of a wealthy southern Viscount who was brought up in Winchester "amongst every elegance and modern refinement".
- What Does This Button Do?: A trebuchet is used to throw shells at the enemy, one of which destroys the entire city.
- Vestigial Empire: The Wersgorix empire.
- Vichy Earth: The Wersgorix plan for Earth is this. It backfires spectacularly.