Sasanian defense lines

The defense lines (or "limes") of the Sasanians were part of their military strategy and tactic. They were networks of fortifications, walls, and/or ditches built opposite the territory of the enemies. These defense lines are known from tradition and archaeological evidence.

In the early period of the Sasanian Empire, a number of buffer states existed between Persia and the Roman Empire, which played major role in Roman-Persian relations. Both empires gradually absorbed these states, and replaced them by an organized defense system run by the central government and based on a line of fortifications (the limes) and the fortified frontier cities, such as Dara.

According to R. N. Frye, the expansion of the Persian defensive system by Shapur II r. 309–379) was probably in imitation of Diocletian's construction of the limes of the Syrian and Mesopotamian frontiers of the Roman Empire over the previous decades. The defense line was in the edge of the cultivated land facing the Syrian Desert.

During the early years of Shapur II, nomadic Arabian tribesmen made incursions into Persia from the south. After his successful campaign in Arabia and securing the coasts around Persian Gulf, Shapur II established a defensive system in southern Mesopotamia to prevent raids via land. The defensive line, called the Wall of the Arabs (Middle Persian: War ī Tāzīgān, in Arabic: خندق سابور‎‎ Khandaq Sābūr, literally "Ditch of Shapur", also possibly "Wall of Shapur"), was a large moat, probably also an actual wall on the Persian side, with watchtowers and a network of fortifications, at the edge of the Arabian Desert, located between modern-day al-Basrah and the Persian Gulf.

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