Mixed government

A Mixed government or mixed constitution is a form of government where different sized groups of people control different types of issues. It integrates different forms of government, like democracy, oligarchy, and monarchy. Mixed government means that there are some issues where the state is governed by the majority of the people, in some other issues the state is governed by few, in some other issues by a single person, often defined in a constitution. Today, this idea is commonly seen as a precursor to that of separation of powers
Mixed governments was common in Ancient Rome.