General Winfield Scott’s occupation of Mexican territory during the Mexican American War from 1846-48 is credited as the progenitor of US Army military occupation doctrine, yet historians have not investigated where and how Scott developed these policies. This thesis examines the possible origins of Scott’s perspectives on occupation. It argues that Scott’s observations in France during the occupation of guarantee in 1815-1816, combined with his military experience and education over the ensuing decades allowed him to formulate the occupation policies he instated during the Mexican American war – especially in Mexico from 1847-48. The US Army of the time period may have adopted French military tactics for war, however the army adopted the British model of military occupation because of Winfield Scott. During 1815-18, the Duke of Wellington led the Quadruple Alliance in the occupation of France after the second defeat of Napoleon. Attempting to break from the continuous cycle of conquest and war, Wellington, along with Viscount Castlereagh and Lord Liverpool enacted an occupation set to ensure future peace. Their benevolent occupation tactics intended to gain the cooperation of the locals by respecting the rule of law, continuing operations of local and civil governments, ensuring the freedom of the Catholic Church, and levying fair reparations. Scott witnessed this during his visit to France in 1815-16, and it arguably left a lasting impression on him. The principles of the occupation of guarantee (even the language Wellington used during the occupation) echo throughout Scott’s career and reappeared in his occupation of Mexico thirty years later. Through his orders and directives in Mexico, Scott attempted to shield Mexicans from violence at the hands of US troops, respected the Catholic Church, demanded fair levies, and maintained the operations of local municipal governments. This thesis does not ignore that Wellington’s occupation of guarantee in France and Scott’s occupation of Mexico thirty years later were different in size, scale, and objectives. However, this thesis does argue that Scott’s unique experiences in France during the occupation of guarantee, combined with his military acumen, and his position at the head of the US Army allowed him to promulgate the progressive military occupation policies seen in Mexico.