The young Percy served in the German Army during World War I and went on to study history and art history at several of Germany's elite universities, including Hamburg, Munich and Heidelberg. In 1922, he completed his doctoral studies at the University of Heidelberg under the medieval historian Karl Hampe. He remained at Heidelberg for two more years to write his "Habilitationsschrift" on the topic of German imperial ideology in the tenth and eleventh centuries, and in particular, how the Holy Roman emperors of the medieval period appropriated the imagery and history of the ancient Roman Empire for their own rule. Published in 1929 as "Kaiser, Rom und Renovatio: Studien und Texte zur Geschichte des römischen Erneuerungsgedankens vom Ende des karolingischen Reiches biz zum Investiturstreit" ("Emperor, Rome and "Renovatio": Studies and Texts on the History of Roman Ideologies of Renewal from the End of the Carolingian Empire to the Investiture Controversy"), Schramm's thesis was a landmark piece of highly original, interdisciplinary scholarship that transformed the way medieval historians approached the subject of political ideology. He demonstrated that art history, a field of study which at the time fell mostly to dilettantes and gentleman scholars, deserved a place in serious academic inquiry alongside history and philology. Schramm's work also emphasized the centrality of symbols and ritual in articulating and defining political ideologies.