Final answer:
Satraps controlled the individual satrapies of the Persian Empire after Darius I's reorganization, acting as powerful regional governors who reported directly to the king.
Step-by-step explanation:
After Darius I’s reorganization of the Persian Empire, the individual governing regions, known as satrapies, were controlled by officials called satraps. The satraps were usually trusted Persian or Median nobles who answered directly to the king and had significant autonomy within their jurisdictions. They wielded considerable power, maintained their own courts, and were responsible for ensuring that their satrapies remained peaceful and continued to deliver their taxes to the empire.