The Achaemenid Empire reached its peak due to governing from Darius I His administrative reforms helped create a strong powerful and influential empire Darius governing of Persia allowed the Persian Empire to become a dominant force Darius created many reforms during his reign over the empire His administrative reforms included dividing the empire into satrapies and introducing a regular form of taxation He also created an imperial law code He led military campaigns in Europe Greece and the Indus Valley He introduced both new governing techniques and new infrastructure to the Persian Empire Finally he introduced the Qanat and the Persian Royal Road Darius I also known as Darius the Great was the third emperor of the Achaemenid Empire Unlike his predecessor Cyrus the Great Darius focused most of his efforts on administrative reforms His successful reign lasted from 522 BCE to 486 BCE Darius governing of the Achaemenid Empire helped the empire reach its peak in power Darius completed the idea of dividing the Achaemenid Empire into twenty three satrapies which was first introduced by his predecessor Cyrus The Achaemenid Empire was such a diverse polyglot empire that it was much easier to rule by dividing it into satrapies Each satrapy was ruled by a royally appointed governor called a satrap A satrap had multiple responsibilities The first was to keep their satrapy loyal to the empire The second was to keep the members of their satrapy happy They also had to give troops to the empire Finally they had to make sure that the empire received annual taxes from their satrapy Due to Persia s tribal nature the men who were appointed satraps were usually old tribal leaders or warriors