The Yuezhi 月支 (also written 月氏, special pronunciation instead of Yueshi) nomadic people roaming the area west of Gansu during the Han 漢 period, also called “Great Yuezhi” (Dayuezhi 大月支). Some western scholars tried to identify the Yuezhi with Asian people described in Greek (Hellenic) or Roman sources, some say Indo-Iranian people like the Scythians or Parthians could be the same people. Once being a mighty power of the Mongolian steppe, the Yuezhi controlled all neighboring peoples. Even a prince of the mighty Xiongnu 匈奴 federation, Modu, was taken as a hostage at the court of the Yuezhi chieftain. After they had been defeated by the Xiongnu and and the Wusun 烏孫 the Yuezhi wandered to the west. On their way they crossed the Dsungharian Basin (Chinese: Zhunga'r Pendi 准噶爾盆地), the Yili River 伊犁河 and arrived in the Soghdiana and Bactrian area (north of modern Iran) where they were called Sakas (Chinese: Sai 塞) and entered the Indo-Persian history. The original area of the Yuezhi was occupied by the Wusun. In the first century BC the Yuezhi divided into five tribes called yabghu (Chinese: xihou 翕侯), the mightest of these, the Guishuang 貴霜, incorporated the others, and founded the empire of Kushāna, also known as Tukhāristān or Tukhāra (Tokhara, Tochara, Chinese: Tuhuoluo 吐火羅). The Yuezhi spoke an Indo-European language that is known as Tocharian with two different dialects, Tocharian A and B. Their script (see example to the right) is derived from the Gupta type of the Brahmi script that was used by the northern Indian rulers in the 5th and 4th century BC. The oldest documents in Tocharian script date from the 7th century.