After studying a number of real and theoretical city-states' constitutions, Aristotle classified them according to various criteria. On one side stand the true (or good) constitutions, which are considered such because they aim for the common good, and on the other side the perverted (or deviant) ones, considered such because they aim for the well being of only a part of the city. The constitutions are then sorted according to the "number" of those who participate to the magistracies: one, a few, or many. Aristotle's sixfold classification is slightly different from the one found in "The Statesman" by Plato. The diagram above illustrates Aristotle's classification.