Is there a special name to describe the formation of knights that form a row of arches with their swords (for a special person to walk through)?
Was such a formation historically accurate, or only something depicted in movies and art?
If real, which countries/cultures, time periods, and circumstances would it have been used in?
Congusbongus was correct. I'm submitting the answer because no answer has been submitted. I don't think it goes back to the middle ages. In the United States it's called the "saber arch" and we get it from the British Navy.
It's a tradition at weddings of military service members, typically when exiting the building in which the wedding ceremony took place. Typically performed by members of the groom/brides? service branch/unit.
Germany and Austria have a similar ceremony for fraternities. https://en.wikipedia.org/wiki/Saber_arch