There were things like the old Roman laws that defined the rights, privileges, and obligations of Roman citizens. Or the various constitutions of the old Greek poleis, which similarly guaranteed the freedom of the citizens. Or even the Hammurabi code, if you squint a bit.
“A decent job” is subject to interpretation, but I find very difficult to argue that the Magna Carta was the first, even if it was very significant.
“A decent job” is subject to interpretation, but I find very difficult to argue that the Magna Carta was the first, even if it was very significant.