Separation of Powers:The division of governmental authority into distinct branches (executive, legislative, and judicial) to prevent the concentration of power and provide checks and balances.
Checks and Balances:A system of mutual control and limitation of power among the different branches of government to prevent any one branch from becoming too dominant.
Polybius: A Greek historian who developed the theory of the mixed constitution, arguing that the ideal government should combine monarchy, aristocracy, and democracy to ensure stability and prevent the cycle of constitutional change.