The Evolution of Contract Society

Modern societies pride itself on making all citizens equal before law.  What is the historical evolution of written law?

When describing political leaders of Achaean during the Heroic Age of Greece (think 1200 B.C.), Durant states, "His degrees are the laws, and his decisions are final; there is as yet no word for law."
Will Durant.  The Story of Civilization.  Part II.  The Life of Greece.  The Heroic Age.

Of course, without law, there can be no contract society.  Men are at the mercy of arbitrary power.  The Greeks may have discovered many things, but political wisdom was still nascent when the Iliad was written.

Although in hindsight Rome was no gentle creature, it was in Rome's political structure where contract society began.  The Christian apostle Paul was once taken into custody during a riot, and as the guards were about to beat him, Paul asserted, "Is it lawful for you to scourge a man that is a Roman, and uncondemned?"  It was not lawful, and Pual's appeal to law immediately halted the guards.  Paul was then  brought before the governor, Porcius Festus, who tried to convince Paul to submit himself to Jewish law, but all Paul had to do was say, "I appeal unto Caesar."  The response from Festus was, "Has thou appealed unto Caesar?  Unto Caesar shalt though go."

Isabel Paterson tells this story of Paul to make the following assertion, "The crux of the affair is that a poor street preacher, of the working class, under arrest, and with enemies in high places, had only to claim his civil rights and none could deny him...The value of the idea of law in its primary use of framing legislation is clear.  It sets moral sanctions above force, while recognizing human fallibility."
Isabel Paterson.  The God of the Machine.  Chapter 3.

Although it would undergo much transformation, this concept of equality before law was essential to providing the modern, liberal democracies where the fortunate of the world currently reside.