LEICESTER, England — For more than 500 years, King Richard III has been the most widely reviled of English monarchs. But a stunning archaeological find this month here in the English Midlands — a skeleton that medieval scholars believe is very likely to be Richard’s — could lead to a reassessment of his brief but violent reign.

If 12 weeks of DNA and isotope testing confirm that the remains found amid the ruins of an ancient priory are the 15th century king’s, those who believe that Richard has been the victim of a campaign of denigration — begun by the Tudor monarchs who succeeded him and deeply entrenched over the centuries in British popular consciousness — hope the renewed attention will spur scholarship that will correct the injustice they say has been done to his reputation.

It is a debate that has raged with varying intensity since at least the late 18th century. And at its heart is this: Was Richard the villain his detractors expediently made him out to be, or was he, as supporters contend, a goodly king, harsh in ways that were a function of an unforgiving time, but the author of groundbreaking measures to help the poor, extend protections to suspected felons and ease bans on the printing and selling of books?...