From Greek demos (people) and kratia (authority), hence rule by the people; contrasted with rule by the few (oligarchy) or by one (monarchy or tyranny); also known as a liberal democracy. Since the Greeks first introduced demokratia in many city states in the 5th-c BC, there has been disagreement about what constitutes the essential elements of democracy. One debate concerns who should compose the people, and only in the 20th-c did this notion come to be viewed as covering the total adult citizenship. Another relates to how the people should rule, particularly in relation to the increasing size of states, which has resulted in a shift from direct democracy to systems of representation. Today it is widely accepted that because the people are too numerous and scattered to come together in assemblies, decision-making has to be handed over to a small group of representatives. Elections, including the right to choose among different groups of representatives offering different doctrines and party programmes, have therefore become seen as essential to democracy. Further necessary conditions are the legal equality of citizens, and the free flow of information to ensure that citizens are in an equal and informed position to choose and hold accountable their rulers. Some radicals argue that economic equality is also necessary, but moves towards economic democracy have been limited.