Political economy, with its roots in the European 17th and 18th centuries, was the forebear of what developed in the twentieth century into the two separate disciplines of political science and economic. However, it has become defined in the last twenty years as that sub-discipline of political science and economic which examines the relationship of the individual to society, the economy, and the state with a particular focus on state-market interactions and intersections. It is the study of relations and choices, of structures and institutions, of scales from the personal and local to the national, international, and global. Its originators include John Locke, Thomas Hobbes, Adam Smith, Karl Marx, and Max Weber. Including choice theory and market theory, system theory, development theory and public policy theory, contemporary political economy examines the historic and human behavioural linkages among values/morals, politics, economic reality and economic reasoning. Its prime question concerns the role of politics in the economy and the effects and constraints of the economy on the power and functions of politics and of the state.