''The Excalibur Alternative'' is a 2002 science fiction work by Creator/DavidWeber, expanding on his earlier short story ''Sir George and the Dragon'', and shares a universe with Creator/DavidDrake's ''Literature/RanksOfBronze''.

14th century English knight Sir George Wincaster and his men are caught in a horrid storm en route to France. Saved by aliens, they find that their saviours' motives are hardly altruistic; the aliens want to use them as hatchetmen and have the power to quell overt rebellion. However, the thirst for freedom is not so easily quenched, and after a long time a ghost of a chance appears to them.

!This novel contains the following tropes:

* BigDamnHeroes: [[spoiler: The Avalon Empire--the heroes and their descendants, basically--arrive just in time to save the rest of humanity from a Federation extermination attempt.]]
* DefeatingTheUndefeatable: In the DistantFinale, [[spoiler: a supposedly unbeatable Federation battle squadron is handily defeated by the Avalon Empire's space navy.]]
* DistantFinale: The last couple of chapters happen after a significant amount of time has passed for the protagonists.
* FeudalFuture: The Avalon Empire, which spans several solar systems, has a feudal structure with an Emperor in charge.
* HappilyMarried: Sir George and Lady Matilda are very much in love.
* HumansAdvanceSwiftly: Humanity's technology advances about twice as fast as is normal for other species. The galactic authorities, whose civilization and technology have remained static for millennia, find this ''terrifying''.
* HumansAreSpecial: Humans are apparently the first species to really threaten the Federation.
* HumansAreWarriors: The trade guild the villain belongs to uses humans to fight other "primitive" species, since they're forbidden to use their own weapons against them. They're effective because unlike their opponents, they're disciplined soldiers.
* OutsideContextProblem: The aliens that abducted the heroes were this, and the heroes become this to the alien races they are being used against.
* ReallySevenHundredYearsOld: Life extension technology means that by the end of the book, Sir George and the others qualify.
* TheReptilians: The villain's bodyguards are silent reptilian aliens that the English army call "dragon-men" and the Federation call the Ternaui. They turn out to be telepathic, explaining the silence, [[spoiler: as well as being just as angry as the humans are about their enslavement by said villain. They make an alliance with Sir George to kill their master and take over the ship, and appear at the end as part of the Avalon Empire.]]
* ZerothLawRebellion: The alien master overlooked the part where [[ThreeLawsCompliant the laws]] are supposed to say "[[spoiler: ...or, through inaction, allow the master to come to harm]]."