"On Dictatorship" was followed by another essay in 1922, titled "Politische Theologie" (political theology); in it, Schmitt, gave further substance to his authoritarian theories, analysing the concept of "free will" influenced by Christian-Catholic thinkers. The book begins with Schmitt's famous, or notorious, definition: "Sovereign is he who decides on the exception." By "exception", Schmitt means the appropriate moment for stepping outside the rule of law in the public interest (see discussion of "On Dictatorship" above). Schmitt opposes this definition to those offered by contemporary theorists of sovereignty, particularly Hans Kelsen, whose work is criticized at several points in the essay.