The Khmer Empire, also known as the Angkor civilization, was an important trading and political force in southeast Asia between about 800 and 1300 AD. Encompassing all of what is today Cambodia, southeastern Thailand and Vietnam, the Angkor civilization could not have accomplished all of what it did without the creation of a elaborate road system to connect its farflung cities with the capital of Angkor.
History of the Khmer Road System
Traditionally, the road system construction is attributed to King Jayavarman VII, who ruled Khmer between AD 1182-1218, and who is credited with the expansion of the empire to its fullest extent. Hendrickson (2010) investigated this claim in detail, identifying the available inscriptions and documented events that imply the existence of roads, and came to the conclusion that Jayavarman was clearly associated with the construction of 17 fire shrines along the northwest road to Phimai.
But, the other portions of the system--including the roads, water tanks, bridges and resting places--appear to pre-date Jayavarman's reign by at least a couple of centuries. Hendrickson argues that the first Khmer road project must have been at least as early as the 10th century, during the reign of Jayavarman IV (AD 921-944), when the capital was moved from Angkor to Koh Ker some 80 km to the northeast. Further, says Hendrickson, like other successful imperial road building projects, that of the Khmer Empire almost certainly began with an existing road system and elaborated it as conditions required.
Road Construction
At its most complex, the Khmer road system was comprised of six main arteries extending out of the capital city of Angkor Wat for a total of ~1,000 kilometers (~620 miles). Secondary roads and causeways served local traffic in and around the Khmer cities. The roads were fairly straight, and constructed of earth piled from either side of the route. The road surfaces were up to 10 meters (~33 feet) wide and in some places were raised to as much as 5-6 m (16-20 ft) above the ground.
Six roads led out from Angkor. The northwest route led 250 km (~155 mi) north through Phnom Rung to the town of Phimai, Thailand. A western route led to Phnom Srok and Sdok Kak Thom, a distance of some 150 km (~93 mi). The lower southeast route led along the Thonle Sap lake and eventually ended up at Prasat Andet and Sambor Prei Kuk, about 175 km (~108 mi). The upper southeast road led to Beng Mealea and then Preah Khan for a distance of approximately 75 km (~47 mi); and the northeastern route led 250 km through Koh Ker to Vat Phu, Laos on the Mekong River.
Facilities
Considerable efforts were expended on road architecture, including corbelled arch bridges and rectilinear earthen tanks providing water for draft animals and travelers. The roads were dotted with monasteries, called asramas, and resting places called samnak. Over a hundred asramas were built by the tenth century king Yasovarman I. Wooden samnuks built along the major transportation routes were common, according to historical sources.
Two main types of masonry resthouses were constructed along the roadways: temples d'etape and sandstone fire shrines (called dharmasalas). These shrines were placed between 12 and 14 km (8-10 mi) apart, corresponding to a half-day of travel. Wooden bridges and buildings were also constructed, although archaeological evidence of these have not as yet been identified.
Uses of the Khmer Road System
One of the primary economic reasons for the road system was the movement of goods into the capital city. Goods brought into Angkor along the roads included salt, boiled from seawater in the Mekong Delta or mined from the mountain deposits in northeastern Thailand. Mountain salt in particular was moved along the northwestern route from Phimai. Iron, used for weapons and agricultural implements, came from significant iron outcrops near Phnom Dek, and was moved via the eastern road to Preah Khan's iron smelting facilities. Copper and bronze were used to create ornaments and statuary; copper and tin sources have been identified in southern Laos near Vat Phu, the eastern terminus of the Northeast road.
The roads also reflect political and religious barriers and intersections with mountain passes, natural hills, rivers and river catchments. The ability to move raw materials to their production zones and on to their markets would have been a critical element in maintaining power: roads allowed that movement around the landscape, across natural barriers and to other transportation corridors. The roads allowed access to scattered temples and temple pyramids important to the Angkor cosmology. The system was intersected with the immense and important aqueduct system which supported water catchment, storage and redistribution to Angkor and surrounding communities.
Archaeology of the Khmer Road System
Archaeological studies mapping roads within the Khmer Empire was conducted by the Living Angkor Road Project, with support from the University of Sydney and Silpakorn University. This project used a combination of existing historical maps, standard archaeological survey techniques, and a variety of remote sensing techniques including aerial photography, geographical information systems.
Sources
This glossary entry is a part of the About.com guides to Angkor Civilization and Ancient Road Systems, and the Dictionary of Archaeology.
Evans D, Pottier C, Fletcher R, Hensley S, Tapley I, Milne A, and Barbetti M. 2007. A new archaeological map of the world’s largest preindustrial settlement complex at Angkor, Cambodia. Proceedings of the National Academy of Sciences 104(36):14277-14282.
Hendrickson M. 2011. A transport geographic perspective on travel and communication in Angkorian Southeast Asia (ninth to fifteenth centuries AD). World Archaeology 43(3):444-457.
Hendrickson M. 2010. Historic routes to Angkor: development of the Khmer road system (ninth to thirteenth centuries AD) in mainlad Southeast Asia. Antiquity 84(324):480-496.
Higham, Charles. 2001. The Civilization of Angkor. Weidenfeld & Nicolson, London.
Sanderson DCW, Bishop P, Stark M, Alexander S, and Penny D. 2007. Luminescence dating of canal sediments from Angkor Borei, Mekong Delta, Southern Cambodia. Quaternary Geochronology 2:322–329.
