He created 20 provinces (satrapies), ruled in the King’s name by satraps. They sent taxes and troops to the king. They were effective in the sense that they stopped the need for ‘micromanagement’ by the King of a vast and unwieldy empire, and there was a series of checks to ensure that satraps ruled well. But, inevitably, localised powerbases may have encouraged local revolts by ambitious satraps.