The empire known for its Persian postal system and extensive road networks was the Achaemenid Empire, which thrived from the 6th to 4th century BCE. Established by Cyrus the Great, it introduced efficient administrative practices that facilitated communication and trade across vast territories. The construction of the Royal Road enabled swift movement of information and goods, contributing to the empire's stability and influence. This sophisticated infrastructure played a crucial role in the Achaemenid Empire’s administration and integration of diverse cultures.