Constitution (Civ4)/Civilopedia

A "constitution" is a system that establishes the fundamental rules by which a nation is governed. Generally, a constitution describes the relationship between the government and the people, and the relationships between the various parts (or branches) of the government. A constitution will lay down how the rulers of the country are chosen and describe the limits of their power. Many nations, such as the United States, have written, codified constitutions, while some, such as the United Kingdom, have unwritten constitutions.
Aristotle invented the concept of constitutions in the 3rd century BC. In 622 AD, the Prophet Muhammad created the first written constitution, the "Constitution of Medina." King Henry I of England proclaimed the "Charter of Liberties" in 1100 AD, and in 1215 the English nobility forced King John to sign the "Magna Carta."
The most important part of the Magna Carta, Article 39, established the concept of "habeas corpus" (literally, "you should have the body") which constrained the king from exiling, imprisoning, or killing anyone without "due process" of law. The "due process" clause of the Fifth Amendment in the US Constitution is directly descended from Article 39.