Which empire built the road system known as the Royal Road?

The Achaemenid Empire built and maintained the Royal Road across the ancient Persian Empire.

The route was developed under Darius I, who ruled from 522 to 486 BCE. It connected the imperial centers of Susa and Persepolis with Sardis in western Anatolia, covering roughly 2,700 kilometres according to the Greek historian Herodotus.

Royal couriers used a chain of stations to carry messages quickly across the empire. Herodotus praised the system in describing how neither snow, rain, heat, nor darkness supposedly stopped the king’s messengers. The road also supported military movement, administration, taxation, and commerce.

The Royal Road was not necessarily one continuous paved highway in the modern sense. It was a network of routes and facilities that the state protected and serviced. Later rulers and empires reused parts of the network, but the famous imperial system is specifically associated with the Achaemenid Persian state.