The events of Part 4 take place in the Dordogne River Valley in France on April 7, 1357, in the midst of the Hundred Years War. The Hundred Years War was a series of armed conflicts fought intermittently between the kingdoms of England and France during the Late Middle Ages, from 1337 to 1453. Drivers of the internecine conflict were English invasions of French land and the right of King Edward III of England to the French throne. Battles were sporadic and often fought by mercenaries. One such mercenary was the French Arnaut de Cervole (c. 1320-1366), a former-priest-turned-mercenary known as “the Archpriest.” After the French king, John II, was captured by the English and could no longer pay his troops, many of these mercenaries, including Cervole, turned to brigandry. By 1357, Cervole led a company of approximately 2,700 men. (“Fourteenth-Century Mercenaries.” United States Naval Academy). These events provide a colorful backdrop for Michael Crichton’s historical fiction.

In Timeline, Arnaut is trying to take the castles of La Roque and Castelgard and the surrounding land from the English Lord Oliver. The area’s mill and market are important sources of tax revenue that Arnaut wants to control.