While in London, Adams learned of a convention being planned to amend the Articles of Confederation. In January 1787, he published a work entitled "A Defence of the Constitutions of Government of the United States". The pamphlet repudiated the views of Turgot and other European writers as to the viciousness of state government frameworks. He suggested that "the rich, the well-born and the able" should be set apart from other men in a senate – that would prevent them from dominating the lower house. Adams's "Defence" is described as an articulation of the theory of mixed government. Adams contended that social classes exist in every political society, and that a good government must accept that reality. For centuries, dating back to Aristotle, a mixed regime balancing monarchy, aristocracy, and democracy – that is, the king, the nobles, and the people – was required to preserve order and liberty.