World War II also delayed Lyon's marriage to Mary Elizabeth Lewis, a fellow student at Baldwin-Wallace.
Mary was the perfect personal and professional companion, having majored in classics and possessing a keen grasp of Latin.
[5] In June 1946, Lyon and his wife Mary moved to Ithaca, New York, to attend Cornell University for his Ph.D. in history.
Henri Pirenne, a renowned Belgian medieval historian, theorized the Roman Empire ended when subsistence living replaced trade.
Lyon found material in the Belgian archives to revise his thesis on the transition from feudal to non-feudal contracts in England and the Low Countries during the late Middle Ages.
[1] Lyon received this offer largely based on his thesis he revised in Belgium, From Fief to Indenture: The Transition from Feudal to Non-Feudal Contract in Western Europe.
From 1965 until his retirement in 1986, Lyon was the Barnaby C. and Mary Critchfield Keeney Professor of History at Brown University in Providence, RI.
[citation needed] While at Brown, Lyon also researched the life of Henri Pirenne and the Annales School of History.
[5] Working as a team, Lyon and his wife, Mary, translated The Wardrobe Book of William de Norwell 12 July 1338 to 27 May 1340.
This work is a primary source of English diplomacy and logistics during the early stages of the Hundred Years’ War.