The men who fought in Napoleon's Grande Armee built a new empire that changed the world. Remarkably, the same men raised arms during the French Revolution for liberte, egalite, and fraternite. In just over a decade, these freedom fighters, who had once struggled to overthrow tyrants, rallied to the side of a man who wanted to dominate Europe. What was behind this drastic change of heart? In this ground-breaking study, Michael J. Hughes shows how Napoleonic military culture shaped the motivation of Napoleon's soldiers. Relying on extensive archival research and blending cultural and military history, Hughes demonstrates that the Napoleonic regime incorporated elements from both the Old Regime and French Revolutionary military culture to craft a new military culture, characterized by loyalty to both Napoleon and the preservation of French hegemony in Europe. Underscoring this new, hybrid military culture were five sources of motivation: honor, patriotism, a martial and virile masculinity, devotion to Napoleon, and coercion. Forging Napoleon's Grande Armee vividly illustrates how this many-pronged culture gave Napoleon's soldiers reasons to fight.