Writing, which is an essential aspect of civilization, was indeed invented by the Sumerians well before 5^th century BC Greece.

However, in terms of governance, the Persians and everybody else used the same system (government by some 'Alpha male', with perhaps some subservient allies) most commonly used in apes, including non-human ones, like chimps and gorillas.

Most peoples' instincts draw them to this so strongly that they'll invent some imaginary eternal alpha-male dictator/emperor/king/warlord/lord-deity to worship, lest, god forbid, they should find themselves without one.

What the Greek miracle achieved is to invent (besides philosophy/science, the Logos/logic, reason over superstition, medicine, etc.) politics, Democracy and everything else we consider truly civilized.

Basically, that you're not, today, the subservient bitch of some warlord or rabbinate (claiming to speak for some invisible supreme warlord in the sky) is thanks to some great thinkers in 5^th century BC Greece.