I think the answer is metal
The Spartans focused more on militaristic strength than on philosophical and intellectual pursuits.
They gave more respect to women than other Greek city states.
Their government was less democratic than other areas of Greece.
There were multiple groups that joined forces to overthrow the Assyrians
The development of writing allowed the memorization of laws, business transactions, records of account, including taxes, etc. It demonstrated the superiority of the written word over oral memory which can be faulty, or perhaps deliberately misstated. It was not by coincidence that the first writing was done on clay tablets which hardened, and it was thereby "written in stone," and could not be changed. It was there for all to see.
