Hulwan

Hulwan was an ancient town on the Zagros Mountains in western Iran, located on the entrance of the Paytak Pass, nowadays identified with the village of Sarpol-e Zahab.

Later Arab tradition, as recorded by al-Tabari, considered the town a Sasanian foundation dating to Kavadh I (reigned 488–496, 498–531), but it is far more ancient: it was known since Assyrian times as Khalmanu, when it lay on the border between Babylonia and Media. To the Seleucids, it was known as Chala (Greek: Χάλα) and was the capital of the district of Chalonitis (Χαλωνῖτις). According to Diodorus Siculus, the name derives from the settlement of Greek captives from Boeotia by Xerxes, who founded the town of Celonae or Kelonai (Κέλωναι).

Under the Sasanian Empire, the district of Hulwan was called [Khusraw] Shad Peroz ("the joy of Khusraw the victorious"), and the city itself probably Peroz Kavad ("victorious Kavad"). After the Muslim conquest of Persia, the words were Arabicized and became known as: [Khusraw] Shadh Firuz and Firuz Qubadh. Although like the rest of Media it belonged to the quarter (kust) of the North, under Khosrau II (r. 590–628) it was included in the quarter of the West, along with Mesopotamia, as the Sasanian rulers began to use the Zagros Mountains as a summer retreat away from the capital of Ctesiphon on the Mesopotamian plain.

...
Wikipedia