An Imperial Frontier and its Landscape: the Gorgan and Tammisha Walls in North-East Iran

The Gorgan Wall is c. 195 km long, and it is possible that it continues in the west and east beyond the section known so far. It is, to our knowledge, the longest ancient barrier in Asia, outside China. The Great Wall of China (in fact not a single wall), made of, or faced with, stones or bricks, dates to 16th and 17th c. AD and not, as commonly thought, to the 3rd c. BC. Its ancient predecessors by contrast did not use ashlar or bricks. Little, incidentally, is known about these ancient Chinese linear earthworks, but it is possible that some of them exceeded the Gorgan Wall in length. The scale of the Wall of Gorgan compares also favourably with its most elaborate ancient counterparts in Europe. Being longer than its two famous British counterparts, Hadrian's Wall and the Antonine Wall, only the 548 km-long German 'Limes' reaches a greater length than the Gorgan Wall. It is worth noting that the German 'Limes' consisted in its most developed form of a rampart, ditch and palisade in the west and a 166 km-long thin wall, presumably without walkway, in the east. If we exclude earthworks, it thus appears that the Gorgan Wall may have been the longest wall anywhere in the ancient world.

Like some of its Roman counterparts, it is lined by a chain of forts. 36 such military compounds are known along the Wall, ranging in size from c. 1.4 to 7.2 ha. This suggests that this massive linear barrier was designed for a substantial standing army. While linear military barriers are today the very epitomes of Roman military architecture, they were matched, if not exceeded, in scale and sophistication by a monument created by Rome's eastern neighbour.

The geographic location of the Gorgan Wall, running from, presumably, the ancient shore line of the Caspian Sea into the Elburz Mountains in the East, leaves little doubt that one of its principal purposes was to protect the Gorgan Plain and its hinterland from incursions from the north. Another function, only recognized in the past five years by our Iranian colleagues, and confirmed and elaborated by our 2005 landscape survey, was that a major irrigation canal led along much of its north side. As a result the spoil from the canal could be used for the construction works. The sheer scale of the irrigation system, which was fed by one of the largest artificial reservoirs in the ancient Near East, provides an impressive testimony to the organisational skills of the state which had created it. Prior to the robbing of its bricks, ancient Persia's largest monument, must have left a deep impression on those who saw it. It was thought (almost certainly erroneously) to have been erected by one of the most famous personalities in Ancient History, Alexander the Great, and is known as Sadd-i Iskandar (Alexander's Wall). Whether a passage in the Holy Koran (18, 94-7) refers to this or to a different border wall remains disputed.

Yet our knowledge of the Gorgan Wall is sketchy. No complete plan of any interior building in any of the forts is known, nor is there agreement on the date of its construction. Suggestions range from the 2nd c. BC to the 6th c. AD. While a 6th-c. date has been suggested for the nearby Wall of Tammisha, the evidence is even less conclusive.

Our project will explore one of the most sophisticated, yet least known, barriers in the ancient world. It promises to reveal the date of construction and occupation of the walls and of associated installations and settlements, their architecture, function and natural environment. To achieve this, we will employ scientific dating and other modern techniques, ranging from magnetometer survey and the study of satellite images to the analysis of mortar, charcoal, other plant remains and bones. The project will provide major insights into the culture and history of the Partho-Sasanian Empires and into the evolution of advanced linear barrier and water supply systems in a global context.