A constitution is a set of principles by which a state is governed. Unlike the American constitution, Rome’s constitution during the period of the Republic was never written down. It evolved over time, largely as a result of what has been called the conflict of the orders—that is, the struggle for power between the Patricians (the Roman aristocracy) and the Plebeians (the Roman commoners). This two hundred year conflict produced a number of concessions granted to the Plebeians that gave them greater representation in the Republic. The mature Roman Republic was a complex governmental system of checks and balances, with various political branches (executive magistrates, the Senate, and legislative assemblies) responsible for the governance of different aspects of public affairs.