Gates of Alexander

The Gates of Alexander, also known as the Caspian Gates, is a term that refers to a mountain pass that is meant to be associated with Alexander the Great, and in antiquity, especially refers to one enclosed by a physical barrier to prevent an incursion from barbarian tribes, imagined as a symbolic boundary separating the civilized from the uncivilized world. Due to confusion over the exact location of this pass, this term had come to be used for multiple sites, including the original in Iran but later came to dominantly be used for a region in the Caucasus due to a confusion described already by Pliny the Elder in the first century. Only the passage at Rhagae between Media and Parthia, which Alexander crossed while pursuing Darius III, is said to be linked with the historical Alexander. Today, the term "Gates" refers, not to physical gates, but to several mountain passes in this region of the world which acted as "gates" from one area to another.

The name "Caspian" Gates originally applied to the narrow region at the southeast corner of the Caspian Sea, through which Alexander actually marched in the pursuit of Darius III, although he did not stop to fortify it. The name was transferred to the passes through the Caucasus, on the other side of the Caspian, by the more fanciful historians of Alexander.

In later literature, the Caspian Gates has also been identified with two other locations: the Pass of Derbent, Russia, or with the Pass of Dariel, a gorge forming a pass between Russia and Georgia with the Caspian Sea to the east. Tradition also connects it to the Great Wall of Gorgan (Red Snake) on its south-eastern shore. These fortifications were historically part of the defence lines built by the Sassanid Persians, while the Great Wall of Gorgan may have been built by the Parthians.