Why is government usually divided in exactly three specific branches?

Question

In most countries, government is divided into legislative, executive and judicial branch. For what reasons is this division to prevalant? Why isn't government divided in some other way (e.g. there could be financial branch, internal affairs branch, etc.)? I wasn't able to answer this question on my own and all the resources I was able to find were descriptive rather than analytical.

Answer 1

A major influence for governments having three branches of government comes from the Enlightenment Period. Baron de Montesquieu suggested government powers should be separated. This idea led to separation of powers and the system of checks and balances. Groups such as the Founding Fathers of the United States used Montesquieu's ideas to establish their government. The idea of how to separate powers and who should have the power in government was fiercely debated at the Constitution Convention. The Legislative (Law-making), Executive (Execute the laws) and Judicial (Interpreting laws) Branches were what the Founding Fathers thought was the best approach to keeping one branch becoming more powerful than the other two.

There are examples of differing approaches to government branches. For instance, Venezuela has five branches of government: executive, legislative, judicial, electoral and citizen.