remains Merv consists of a few discrete walled cities very near to each other constructed on uninhabited land by builders of different eras, used, and then abandoned and never rebuilt. Four walled cities correspond to the chief periods of Merv's importance: the oldest, Erkgala, corresponds to Achaemenid Merv, the smallest of the three. (also known as Gyaur Gala), which surrounds Erkgala, comprises the Hellenistic and Sassanian metropolis and also served as an industrial suburb to the Abbasid/Seljuk city, Soltangala—by far the largest of the three. The smaller Timurid city was founded a short distance to the south and is now called Abdyllahangala. Other ancient buildings are scattered between and around these four cities; all the sites are preserved in the “Ancient Merv Archaeological Park” just north of the modern village of and east of the large Soviet-built city of Mary. Erk Gala Erk Gala (from Persian, "the citadel fort") is the oldest part of the city of Merv complex. Built in the 7th century BC, Erk Gala was built as a Persian Style fortress controlling the oasis on the Murghab River. The Erk Gala fortress later served as the acropolis for the Hellenistic city and later the Arc of the Islamic city. Gäwürgala The foundation of (Turkmen from the Persian "Gabr Qala" ("Fortress of the Zoroastrians") occurred in the early Hellenistic era under the rule of the Seleucid king Antiochus I. The city was continuously inhabited under a series of Hellenistic rulers, by the Parthians, and then under the Sassanids, who made it the capital of a satrapy. was the capital of the Umayyad province of Khurasan and grew in importance as Khurasan became the most loyally Muslim part of the Iranian world during Islam's first two centuries. most visible remaining structures are its defensive installations. Three walls, one built atop the next, are in evidence. A Seleucid wall, graduated in the interior and straight on the exterior, forms a platform for the second, larger wall, built of mudbricks and stepped on the interior. The form of this wall is like other Hellenistic fortresses found in Anatolia, though this is unique for being made of mudbrick instead of stone. The third wall is possibly Sassanian and is built of larger bricks. Surrounding the wall were a variety of pottery sherds, particularly Parthian ones. The size of these fortifications is evidence of Merv's importance during the pre-Islamic era; no pre-Islamic fortifications