In 1386, a few days after Christmas, a huge crowd gathered at a Paris monastery to watch two men fight a duel to the death--a clash meant to "prove" which man's cause was right in God's sight. The dramatic true story of the knight, the squire, and the lady unfolded during the devastating Hundred Years War between France and England, as enemy troops pillaged the land, madness haunted the French court, and the Great Schism split the Church.

The story of three larger-than-life characters caught up in a fatal triangle is recounted in The Last Duel: A True Story of Crime, Scandal, and Trial by Combat in Medieval France (Broadway Books), written by Eric Jager, professor of English. Jager--whose research and teaching focuses on, among other fields, Old English, Middle English, and classical culture--produced an account of medieval France that brings to light the true story of the final "duel to end all duels": a trial by combat that pitted a knight against a squire accused of violating the knight's beautiful young wife.

Jager's extensive research in Normandy and Paris--work that included exploration of family records of archives so comprehensive that they date back to the Middle Ages--turned up unpublished documents that shed new light on the case and the tangle of mysteries and motives at its core. For Jager, conducting research on a period of rebellion, treachery, and plague "was like trying to solve a true-life crime mystery and write a detective story.

"I first got the idea for the book ten years ago while reading a medieval chronicle by Jean Froissart. Froissart was the Dominick Dunne of the 14th Century, and the story of the knight, the squire, and the lady was the high-profile celebrity scandal of the day."

At the heart of Jager's book is Jean de Carrouges, a Norman knight who returned from Paris to find his wife, Marguerite, accusing Jacques Le Gris, her husband's old friend and fellow courtier, of brutally raping her. The knight took his cause before the teenage King Charles VI, the highest judge in France.

Amid Le Gris' vociferous claims of innocence and doubts about the now-pregnant Marguerite's charges (and about the paternity of her child), the deadlocked court decreed a "trial by combat." The decision also left Marguerite's fate in the balance, for if her husband and champion lost the duel, she would be put to death as a false accuser. De Carrouges and Le Gris, in full armor, eventually met on a walled field in Paris before a massive crowd that included the king and many nobles of the realm. A fierce fight on horseback and then on foot ensued during which both combatants suffer wounds--but only one received fatal blows.

"The violent and tragic episode was notorious in its own time," Jager said. "Because of the nature of the alleged crime and the legal impasse it provoked, trial by combat, an ancient but increasingly suspect institution, was thereafter abolished."