Royal Road

The Royal Road was an ancient highway reorganized and rebuilt for trade by Darius the Great, the Achaemenid emperor, in the 5th century BC. Darius I built the road to facilitate rapid communication on the western part of his large empire from Susa to Sardis. Mounted couriers of the Angarium were supposed to travel 1,677 miles (2,699 km) from Susa to Sardis in nine days; the journey took ninety days on foot.