In Dan Jones' novel Essex Dogs, readers see fictionalized portrayals of royalty and knights from the point of view of the foot soldiers under their command in the early years of the Hundred Years' War (a series of wars interspersed with truces between the French and English that began in 1337 and lasted for 116 years). Far from the fantasy of the noble knight, they are often brutal, petty and crude. The archetype of the chivalric knight in shining armor has long been ubiquitous, but what did chivalry actually mean to medieval Europeans? The word itself, which derives from the Latin word for horse, has had multiple meanings over the centuries. Originally, it simply referred to mounted warriors. Later, it came to mean knights—not just any soldier on horseback, but specifically those of noble birth. Finally, by the late 14th century, it had expanded to include the code of ethics those knights were expected to follow.

This code changed over time. Early concepts of chivalry were ...