->''"Hearken, Brother Parvus," said Sir Roger. "I'm weary of this whining about our own ignorance and feebleness. We're not ignorant of the true Faith, are we? Somewhat more to the point, maybe, while the engines of war may change through the centuries, rivalry and intrigue look no subtler out here than at home. Just because we use a different sort of weapons, we aren't savages."''

''The High Crusade'' is a humorous ScienceFiction novel by Creator/PoulAnderson. First published in 1960.

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 -- [[RockBeatsLaser 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:

* AlienInvasion
* AlternateHistoryWank: Played straight and in time taken to [[UpToEleven Biblical proportions]].
* {{Badass}}: Oh so many! Sir Roger, his chief man-art-arms Red John Hameward, Lady Catherine, heck even Brother Parvus and the captive Wersgor officer get their moments.
* BattleCouple: Sir Roger and Lady Catherine.
** Also RulingCouple
* BadassIsraeli: The first humans meet them on their recontact with Earth hundreds of years later is a starfaring Israeli Empire.
* CurbstompBattle: 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.
* DemocracyIsBad: 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 Creator/RolandEmmerich, was made in 1994. It takes the humorous-but-played-straight premise of the book and tries very hard to turn it into Film/MontyPythonAndTheHolyGrail ... InSpace! Sadly, this does not work particularly well.
* EasilyThwartedAlienInvasion: 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!
* EpicFail: 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.
* EvenEvilHasStandards: The Wersgor see nothing wrong with imperialism and genocide, but are appalled at the medievals' use of JackBauerInterrogationTechnique.
* ExactWords: Sir Roger is very good at bluffing while not actually, [[JediTruth 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....
* FalseReassurance
* FeudalFuture: 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, [[spoiler: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.
* FramingDevice: ''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.
* GalacticConqueror: Sir Roger, who manages to take over a huge galactic empire despite having been born a Medieval human knight.
* GoodRepublicEvilEmpire 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 VastBureaucracy and habitually subservient, [[AuthorAppeal similar criticisms]] to those levied against modern Western states by many conservatives.
* HumanityIsSuperior
* HumansAreWarriors
* KnightInShiningArmor: Played with.
* MedievalMorons: Subverted -- and how! The morons end up conquering a spacefaring empire.
* NicknamingTheEnemy: "Bluefaces".
* NoIndoorVoice (Part of how Sir Roger outsmarts the first set of aliens he encounters. [[spoiler: 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]].)
* OutgrownSuchSillySuperstitions: 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.
* RammingAlwaysWorks: 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.
* RealityEnsues: 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 onesself.''
* RisingEmpire: One funded by good honest Englishmen by dint of skillful politics, force of personality, and lying where it's needed.
* RockBeatsLaser: Not to mention rock helps laser. A trebuchet firing nuclear shells? Undetectable by space age sensors? Yes please.
** Wait... why isn't the trebuchet and anyone working it nuked themselves? Also a trebuchet would be in visible range and nuclear shells launched by a trebuchet but not something more... advanced?
*** 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."
* TortureTechnician: One-eyed Hubert. Who is quite pleased when Sir Roger threatens to apply the JackBauerInterrogationTechnique 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... [[PetTheDog right before he goes back to helping his little granddaughter gather daisies.]]
* VestigialEmpire: The Wersgor empire.
* VichyEarth: The Wersgor plan for Earth is this. It backfires spectacularly.