England 1345, and Sir Roger de Tourneville has volunteered to help King Edward III in his war against the French. 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 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.
- Battle Couple: Sir Roger and Lady Catherine. Also a Ruling Couple.
- Badass Israeli: The first humans meet them on their recontact with Earth hundreds of years later is a starfaring Israeli Empire.
- 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.
- Democracy Is Bad: Subverted in that while the Wersgor 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 he Wersgor 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 Wersgor 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 Wersgor 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.
- False Reassurance
- 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 Wersgor 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 Wersgor "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 Wersgor explicitly describing their state as all-powerful and the citizens as reflexively subservient to it and to their superiors. The Wersgor 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, has a useful advantage or two.
- Humans Are Warriors: The ones the aliens pick on, anyway.
- Knight in Shining Armor: Played with. The humans are led by literal knights in shining armor, but they're pragmatic leaders and politicians.
- Medieval Morons: Subverted — and how! The morons end up conquering a spacefaring empire.
- Nicknaming the Enemy: "Bluefaces".
- 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 Wersgor. 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 Wersgor battle fortress, crushing it. Then pissed off cavalry trample down the survivors.
- Reality Ensues: Ironically inflicted on the invading Wersgor. 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.
- 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 Wersgor. 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.
- Vestigial Empire: The Wersgor empire.
- Vichy Earth: The Wersgor plan for Earth is this. It backfires spectacularly.