After the fall of the Mauryan Empire, a number of foreign powers like the Bactrian Greeks, the Shakas, the Parthians and the Kushanas invaded India. They ruled in the western and north-western parts of India. The Kushanas were a branch of the Yue-Chi tribe of Central Asia. The first ruler of the Kushanas was Kujula Kadphises. He was succeeded by Vima Kadphises.
The Kushan Empire was originally formed in the early 1st century CE under Kujula Kadphises in the territories of the former Greco-Bactrian Kingdom around the Oxus River (Amu Darya), and later based near Kabul, Afghanistan.
During the 1st and early 2nd centuries CE, the Kushans expanded across the northern parts of the Indian subcontinent at least as far as Saketa and Sarnath near Varanasi.
The greatest ruler of the Kushana dynasty was Kanishka, who became king after Vima. Kushana conquered Kashmir and established his supremacy over the Indo-Gangetic plains. He occupied Kashgar, Yarkhand and Khotan in Central Asia. Punjab and Afghanistan were also parts of the empire.
Kanishka was a devoted Buddhist. Through his efforts Buddhism spread to China, Central Asia and other countries. He was also a great patron of art and learning. Purushapura (Peshawar) was his capital.
Kanishka’s successors were Vashishka, Huvishka, Kanishka II and Vasudeva. Vasudeva was the last great ruler of the Kushanas. After his death the mighty Kushana Empire quickly disintegrated. The fall of Kushana Empire marked the beginning of political uncertainty in north India which continued for about a century.