CASPIAN GATES, an ancient toponym identifying a ground-level pass that runs east and west through a southern spur of the Alborz Mountains in north central Iran.

In 330 b.c. Alexander the Great pursued the last Achaemenid king Darius III through the Caspian Gates, which were described by Arrian (Anabasis 3.20) as being one day’s march to the east for a traveler of Alexander’s speed, from Rhagae (modern Ray south of Tehran). Partly on this evidence the Caspian Gates have been equated by Jackson and other writers with Tang-e Sar-e Darra, 51 miles (82 km) east of Ray on the Khorasan road (Jackson, pp. 127-37). Pliny describes the Caspian Gates (Caspias portas) as a mountainous pass that forms in part a narrow passage, the rocky sides of which appear to have been exposed to fire. Salt water issues from the rock and collects in a stream (Pliny, Natural History 6.14-15). This description is appropriate for a western segment of Tang-e Sar-e Darra where the barren and eroded rock and clay sides are variously colored dull brown and ochre and where salt leaches from the ground to pollute a small, seasonal stream (Jackson, pp. 132-34; Curzon, Persian Question I, p. 293). Pliny states that upon leaving the Gates one comes at once to the realm of the Caspian (Caspiis) tribes (q.v.), and it was through this connection that the pass derived its name. Pliny adds that the Caspian Sea (Caspium mare) to the north of the Caspian Gates is also named for the Caspian people who inhabited part of its shores (Pliny, 6.17). On the other hand, he complains that some contemporary writers wrongly give the name Caspian Gates to the Gates of the Caucasus in Hiberia (Georgia; Pliny, 6.15). The orientation of the Caspian Gates is further confirmed by Strabo (2.12.4), who states that they extended toward the east bordering on Aria (eastern Afghanistan). Eustathnis (p. 393) calls the Gates “the keys to the earth of Asia,” a description that reflects the importance of the trade route to central Asia, which traversed the pass. A form of the ancient name of the pass was known to the early Islamic geographers Ebn Ḵordāḏbeh and Qodāma, who identify a post-station at the western approach as Kāsb, Iranian Kāsp (see Herzfeld, p. 195).



Eustathnis, Paraphrase of Dionysius Perigetes, Geographi Graeci Minores II, Paris, 1882.

E. Herzfeld, The Persian Empire, Wiesbaden, 1968.

A. V. W. Jackson, From Constantinople to the Home of Omar Khayyam, New York, 1911.

E. Schmidt, Flights over Ancient Cities of Iran, Chicago, 1940 (aerial and ground-level photographs of Tang-e Sar-e Darra, p. 34, pls. 41-42).

(John H. Hansman)

Originally Published: December 15, 1990

Last Updated: December 15, 1990

This article is available in print.
Vol.V, Fasc. 1, pp. 61-62