What did Darius contribute to the empire?
-consolidated and organised the empire into 20 satrapies, each with a governor (satrap)
-constructed the palace at Persepolis and rebuilt the royal site at Susa
-administrative capitals of Ecbatana, Susa, Pasargadae and Persepolis so administration centres could be distributed throughout the empire
-network of roads to allow trade
-canal linking the red sea to the Nile so Persians could trade with the Mediterranean
-new irrigation system in Egypt
-brought the island of Samos under Persian control, and formed alliances with Lesbos and Chios in order to gain access to a powerful Aegean fleet