In his 1937 book "A History of Political Theory", George Sabine collected the views of many political theorists on consent of the governed. He notes the idea mentioned in 1433 by Nicholas of Cusa in "De Concordantia Catholica". In 1579 an influential Huguenot tract "Vindiciae contra tyrannos" was published which Sabine paraphrases: "The people lay down the conditions which the king is bound to fulfill. Hence they are bound to obedience only conditionally, namely, upon receiving the protection of just and lawful government…the power of the ruler is delegated by the people and continues only with their consent." In England, the Levellers also held to this principle of government.