Colchis). Alexander politely refused. Khwarezm was largely independent during the Seleucid, Greco-Bactrian and Arsacid dynasties. Numerous fortresses were built, and the Khwarazm oasis has been dubbed the "Fifty fortresses oasis". Chorasmia remained relatively sheltered from the interests of the Seleucid Empire or Greco-Bactria, but various elements of Hellenistic art appear in the ruins of Chorasmian cities, particularly at Akchakhan-Kala, and the influence of the Greco-Buddhist art of Gandhara, reflecting the rise of Kushan Empire, appears at Toprak-Kala. The early rulers of Chorasmia first imitated the coinage of the Greco-Bactrian ruler Eucratides I. Parthian artistic influences have also been described. From the 1st century BC, Chorasmia developed original coins inspired from Greco-Bactrian, Parthian, and Indo-Scythian types. Artav (Artabanus), a Chorasmian ruler of the 1st–2nd century AD, whose coins were discovered in the capital city of Toprak-Kala, imitated the type of the Kushan Heraios and were found together with coins of the Kushan rulers Vima Kadphises and Kanishka. From the 2nd century AD, Chorasmia became part of the vast cultural sphere corresponding to the rise of the Kushan Empire in the east. Sassanid period Under Shapur I, the Sasanian Empire spread as far as Khwarezm. Yaqut al-Hamawi verifies that Khwarezm was a regional capital of the Sassanid empire. When speaking of the pre-Islamic "khosrau of Khwarezm" (), the Islamic "amir of Khwarezm" (), or even the Khwarezmid Empire, sources such as Al-Biruni and Ibn Khordadbeh and others clearly refer to Khwarezm as being part of the Iranian (Persian) empire. During the reign of Khosrow II, extensive areas of Khwarezm were conquered. The fact that Pahlavi script which was used by the Persian bureaucracy alongside Old Persian, passed into use in Khwarezmia where it served as the first local alphabet about the AD 2nd century, as well as evidence that Khwarezm-Shahs such as ʿAlā al-Dīn Tekish (1172–1200) issued all their orders (both administrative and public) in Persian language, corroborates Al-Biruni's claims. It was also a vassal kingdom during periods of Kushans, Hephthalites and Gokturks power before the coming of the Arabs. Afrighids Per Al-Biruni, the Afrighids of Kath () were a native Khwarezmian Iranian dynasty which ruled as the Shahs of Khwarezm from 305 to 995 AD. At times they were under Sassanian suzerainty. In 712, Khwarezm was conquered by the Arab Caliphate (Umayyads and Abbasids). It thus came vaguely under Muslim control, but it was not till the end of the 8th