Forms of Government refers to the different ways a country, society, or a political unit can be ruled. "Forms of government" encompass the structures and mechanisms that govern the behaviour of individuals within a jurisdiction, aiming to exert power over community politics. 

There are many theories on 'Forms of Government'. The 2 major theories on 'Forms of Governments' are Classical Theory, and Modern Typology.

Classical theory is made by Aristotle. The case history of Athens is an important source to understand his classification of the constitutions. One can understand this fact based on two factors:

1. The number of individuals ruling the state: whether it is one person ruling the state, a few individuals or if it is a rule of many.

2. The intent of the ruler or rulers: whether the ruler is ruling for his state's interest (known as a normal form of government), or whether the ruler is looking after his self-interest (known as a perverted form of government).

The 6 Forms of government was :

• A Monarchy - a country that is ruled by a monarch, and monarchy is this system or form of government. A monarch, such as a king or queen, rules a kingdom or empire.

• A Tyranny - cruel and oppressive government or rule.

• An Aristocracy - a ruling class of individuals, often with high social rank and wealth, who hold significant political and economic power. It can also refer to a form of government where this elite group holds power. 

• An Oligarchy - a small group of people having control of a country or organisation.

• A Constitutional democracy - a system of government where power is held by elected representatives and exercised according to a constitution that defines the rules of governance.

• A Democracy - a form of government in which political power is vested in the people or the population of a state.

According to Aristotle, without any adequate checks on a ruler's power, no form of government would be stable. He believes that power and virtue cannot coexist.

He has provided the cycle of change of governments over time. Kingship, a normal form of government, turns to tyranny when there is an absence of control over the monarch's power. Tyranny leads to a rebellion or a revolution by a few individuals who establish an aristocracy. Aristocracy can deteriorate and turn into an oligarchy, the perverted form. With time, a greater many rebels against oligarchy and supersede it with polity. Polity further decays in democracy when the many rulers begin to seek their self-interest. In the end, a single individual who seems virtuous establishes a monarchy, and the progression of ideal form and perverted form continues in a circular motion.