How was the administration of the Persian Empire carried out?

At the head of the Persian Empire was the king, after him came the governors or satraps, who ruled over the satrapies (certain areas). There were 20 satrapies in ancient Persia. Thus, each satrap made an account of his activities and transmitted it to the king. The division of the Persian state into satrapy took place during the reign of Darius 1. At the same time, Persia was able to reach its maximum size, and therefore, for a long period of time, there were no significant changes in the composition of the satrapies.