To me using cavalier as a term for a knight, especilly in BMs early medieval times, never sits well.
Merriam-Webster.com
Origin of Cavalier
Middle French, from old Italian cavaliere, from Old Occitan cavalier, from late Latin caballarius horseman, from Latin caballus
cav-a-lier noun /First known use: 1589
cavalier adjective / First known use: circa 1641
Encyclopaedia Britannica
cavalier
cavalier, (from Late Latin caballarius, “horseman”), originally a rider or cavalryman; the term had the same derivation as the French chevalier. In English the word knight was at first generally used to imply the qualities of chivalry associated with the chevalier in French and with the kindred cavaliere in Italian and caballero in Spanish. “Cavalier” in English, however, had the pejorative sense of “swashbuckling” or “overbearing.”
In the English Civil Wars (1642–51), the name was adopted by Charles I’s supporters, who contemptuously called their opponents Roundheads; at the Restoration, the court party preserved the name Cavalier, which survived until the rise of the term Tory.
©2012 Encyclopædia Britannica, Inc.
Cavalier for the class, knight (or caballero) for the title.
