The High Crusade

""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.""

A humorous Science Fiction novel by Poul Anderson, first published in 1960.

It's England in 1345, and Sir Roger de Tourneville has volunteered to help King Edward III in his war against the French. Having assembled a band of knights and foot soldiers, Sir Roger prepares to head off to war. But on the eve of their departure, an alien spacecraft -- a scoutship from the Wersgorix Empire -- lands outside the town. Mistaking the ship for a French strategem, Sir Roger and his force storm it, winning the encounter 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. (Not to mention some unexpected tactics.)

With the help of a sole surviving alien acting as an interpreter, Sir Roger grasps the potential the alien craft has as a weapon against the French, and after the French as a tool for liberating the Holy Land. After loading the entire town into the ship, he orders the interpreter to send the craft -- now re-dubbed The Crusade -- to France, but the alien takes advantage of their ignorance and sets the ship on autopilot to the closest Wesgorix colony world.

Arriving at the sparsely-populated planet, Sir Roger does the only thing he can think of to keep the people under his rule and command safe -- attack, on both the military and political fronts. 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, unfortunately, the humans -- not being astrogators, among other reasons -- have no idea where Earth is any more.

""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."
 * Alien Invasion
 * Battle Couple: Sir Roger and Lady Catherine
 * 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.
 * 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.
 * 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.)

""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.""
 * 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....
 * False Reassurance
 * Feudal Future
 * Framing Device
 * Good Republic, Evil Empire (Inverted - the theoretical freedom of the Wersgor 'democracy' is unfavourably contrasted with the securities of the feudal system)
 * Also played with, in that the Wersgor republic is also unfavourably contrasted with the Jain Republic (one of the lesser starfaring powers Sir Roger convinces to join his crusade against the Wersgor), with the Jain republic 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.
 * Humanity Is Superior
 * Humans Are Warriors
 * Knight in Shining Armor (played with)
 * Medieval Morons (Subverted - and how!)
 * No Indoor Voice (Part of how Sir Roger outsmarts the first set of aliens he encounters. .)
 * Outgrown Such Silly Superstitions (the Wersgor. The humans on the other hand are very pious. While there is some tongue in cheek humour 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.)
 * Refuge in Audacity: Thrown into the heart of a intergalactic empire centuries ahead of them in technology, outnumbering them billions (trillions!) to one, Roger's solution is to attack.
 * Rock Beats Laser (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?


 * Torture Technician : One-eyed Hubert. Who is quite pleased when Sir Roger threatens to apply the Jack Bauer Interrogation Technique to the captive Wersgor.
 * Vichy Earth: Wersgor plan for Earth is this. It backfires spectacularly.