Kantorowicz's 1957 study of 1,200 years of monarchy has had a profound affect on the way academics think about the study of history. While many historians mocked the medieval concept that a king could be both a person and the symbol of a country, Kantorowicz took fresh looks at the context of medieval philosophy and politics to explain how this duality safeguarded power and ensured political stability. He went on to identify how monarchies used religious imagery and ideas to enhance and extend power and form states. Analyzing an impressive array of primary material, Kantorowicz showed that leaders used broadly similar symbols across many centuries to achieve their political ends.