Kushan seems to have spread their empire with the help of geo-cultural realm(south, central and west) along with inner and maritime Asia. Indo-Scythians is a term used to refer sakas who migrated into Bactria, Sogdiana, Arachosia, Gandhara, Kashmir, Punjab, Haryana, Uttarpradesh from the middle of the 2nd century BCE to the 4th century CE. Sakas were basically nomad. The first saka king in india was Maus or Moga who established saka power in Gandhara and gradually extended supremacy over north-western India. Gradually control of the area from the Scythians tribes, the Kushans expanded south into the region traditionally known as Gandhara (it is name of an ancient kingdom that was located in northern Pakistan and eastern Afghanistan). It was a centre of international commercial activities . It was an important channel of communication with ancient Iran, India and Central Asia. Kushan established twin capital near present day Kabul and Peshawar than known as Kapisa and Pushklavati respectively.
The Kushans adopted elements of the Hellenistic culture of Bactria. Hellenistic culture means Greek culture, religion, art and literature. They also adopted the Greek alphabet to suit their own language and soon began minting coinage on the Greek model. On their coins, they used Greek language legends combined with Pali legends.
The Kushans believed in predominantly Zoroastrianism. Zoroastrianism means religion and philosophy based on the teaching of prophet Zoroaster and was formerly among the world largest religions. It was probably found sometimes before the 6th century BCE in Greater Iran. Besides it, many Kushan started adopting aspects of Buddhist culture. Like the Egyptians, they absorbed the strong remnants of the Greek culture of the Hellenistic kingdom. The great Kushan emperor Vima Kadphises may have embraced saivism. Saivism is the oldest sect of Hinduism. Shaivism is widespread throughout India, Nepal and Srilanka mostly. Besides it, saivism included parts of south-east Asia especially Malaysia, Singapore and Indonesia.
The rule of the Kushans linked the seagoing trade of the Indian Ocean with the commerce of the silk road through the long civilized Indus-Valley. At the height of the dynasty, the Kushan loosely ruled a territory that extended to the Aral Sea through present day Uzbekistan, Afghanistan and comparative peace of such vast expenses encouraged long distance trade, brought Chinese silks to Rome and created string of flourishing urban centres.