Pretty weird how 300 portrays Persia as a slaver tyranny and the Spartans as live free or die hard chads, but in reality Spartans fought with helots (slave conscripts) and Persia had much fewer slaves in comparison. The east must always be evil, project all our western sins on the east.

Listen to this quote on this period of Iranian history:

On the whole, in the Achaemenid empire, there was only small number of slaves in relation to the number of free persons and slave labor was in no position to supplant free labor. The basis of agriculture was the labor of free farmers and tenants and in handicrafts the labor of free artisans, whose occupation was usually inherited within the family, likewise predominated. In these countries of the empire, slavery had already undergone important changes by the time of the emergence of the Persian state. Debt slavery was no longer common. The practice of pledging one’s person for debt, not to mention self-sale, had totally disappeared by the Persian period. In the case of nonpayment of a debt by the appointed deadline, the creditor could turn the children of the debtor into slaves. A creditor could arrest an insolvent debtor and confine him to debtor’s prison. However, the creditor could not sell a debtor into slavery to a third party. Usually the debtor paid off the loan by free work for the creditor, thereby retaining his freedom.

So they had slaves, as did many empires of the time, but relatively few and mostly debtors working off debt to their creditor directly and not a massive system of war slaves like Sparta had.