I’m reading Pat Kelleher’s No Man’s World trilogy, a well-done tale of British Tommies from the Western Front of 1916 to an alien world. (And, when finished, it will go to the bottom of the long list of reviews to be written up.)
It put me in mind of this, the first version I know of a story putting human soldiers from human history into war on an alien world.
Raw Feed (1992): The High Crusade, Poul Anderson, 1960.
A really fun book in which the plucky, bold Sir Roger de Tourneville not only repels the invading Wergorix from Earth but, through bluff, boldness, and intrigue builds a star empire.
This book reminded me of a couple of stories though with very different outcomes.
The first is the story of King Arthur. The affair (never sexually consummated) between Sir Owain and Lady Catherine and the betrayal (unsuccessful) of Sir Roger reminded of the affair between Lancelot and Guinevere (Lancelot, like Sir Owain, is charming).
The ability of the low tech Englishmen to thwart the Wergorix (no metal to be radar visible, masters at hand to hand combat and sieges, crossbows in space) reminded me of the struggles of the fighter jet pilot to best WWI aircraft in Dean McLaughlin’s “Hawk Among the Sparrows”. Military tactics and technology evolve to fit a certain environment. The victory is not always won by the high tech forces. Sir Roger has a nice bit when he says
“ … 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.”
It’s the guile of Sir Roger (though he modestly says he’s “no master of it … no Italian”) that wins the day. ‘
I was reminded of historian William MacNeill’s thesis that Europe came to dominate the world because of the fierce, prolonged struggle between its different states, a struggle not duplicated elsewhere where one power soon came to be supreme. [This is put forth in his The Pursuit of Power.] This novel is sort of a forerunner to MacNeill’s thesis (which may not be original). (Did the Italians become Machiavellian master of intrigue because they were balkanized so long?)
I liked the humor when aliens interpret Christianity and other aspects of mediaeval culture as being signs of possibly advanced powers, and I liked the English complaining about the barbarous aliens with their lack of wood carving and ornamentation. Brother Parvus was unintentionally witty in his unsureness as to the righteousness of Sir Roger’s cause (and whether congress between man and alien is bestiality).
I also liked the comparison between the breakup of the Roman Empire and the Wersgorix Empire.
Parallax perspective on this is provided by Vintage Novels.
More fantastic fiction is indexed by title and author/editor.
MarzAat 
I first read Poul Anderson as a kid when I found a copy of VAULT OF THE AGES in the school library. After that, I was hooked! Loved the Flannery series. And THE HIGH CRUSADE is another favorite.
Did you see that The High Crusades was picked for the Library of America’s two-volume collection for SF of the 1960s? I read it in junior high and vaguely remember it as being somewhat fun. But does it deserve the literary recognition that LoA confers?
I knew LOA did a volume of 1960s SF. I didn’t know it was in there.
I’d say you could argue its inclusion on a several grounds. You get a sample of Poul Anderson’s adventure sf. You get an example of history mixed with sf with no time travel. It’s actually pretty well worked out in terms of depicting the mind-set of Crusaders. They are, for instance, concerned about knowing when Easter occurs in their new setting.
I suppose it depends on what the editor (Gary K. Wolf, I assume) thought it important to represent in terms of motifs and concepts and styles.
There also be a non-literary factor at work. I’ve heard more than one anthologist complain that literary estates, especially when not run by authors, often have an exaggerated idea of what reprint rights are worth. In fact, I just saw S. T. Joshi a couple of months back stating that, for that reason, he wished he only had to deal with public domain works when editing anthologies.
I know Robert Silverberg, still very much alive, is pretty generous at allowing cheap reprints of his work. It keeps his name out there, and the work is already done. It’s all found money to him.