A dictatorship is an authoritarian form of government, characterized by a single leader or group of leaders with either no party or a weak party, little mass mobilization, and limited political pluralism. According to other definitions, democracies are regimes in which "those who govern are selected through contested elections"; therefore dictatorships are "not democracies". With the advent of the 19th and 20th centuries, dictatorships and constitutional democracies emerged as the world's two major forms of government, gradually eliminating monarchies, one of the traditional widespread form of government of the time. Typically, in a dictatorial regime, the leader of the country is identified with the title of dictator. A common aspect that characterized dictators, is to take advantage of their strong personality, usually by suppressing freedom of thought and speech of the masses, in order to maintain political and social supremacy and stability. Dictatorship and totalitarian societies generally employ political propaganda to decrease the influence of proponents of alternative governing systems.