What are the historical roots of "political Shiʿism" in Iran? Which historical dynamics have contributed the most to trigger the involvement of the Iranian clergy in politics? In the fortieth anniversary of the Iranian revolution, academic answers to these questions appear more relevant than ever. To this end, the article provides a historical framework by focusing on four interrelated episodes: the Tobacco Revolt of 1891-2, the rising of Reza Shah (1921) as the penultimate Shah of Persia, the coup d’état of 1953, and the 1979 Islamic Revolution. Each of these four moments continues to echo in Iran, as well as in a large part of the Middle East.