There were a number of smaller kingdoms coming into existence by the end of the Maurya Empire in 185 BC. Unfortunately, none of the kings of Magadha were powerful enough to keep a hold of all of India. As a result, a series of rather weak dynasties ruled over Magadha, such as Sunga Dynasty, Kanva Dynasty and the Satavahana Dynasty. Invaders from Scythia, Parthia and Central Asia occupied the Northern and the Western Part of India. The Kushanas were a central Asian Nomadic Tribe that breached into the Indian Sub-Continent by 50 AD and ruled till around 320 AD.
It is considered the a nomadic Yue-chi (Yuezhi) tribe moved towards the lands occupied by Indo-Scythian in Gandhara in the latter half of the first century AD. The Yuezhi tribe was able to get hold of Taxila, Indus Basin and the Hindukush. It is said that the first king of Kushana Dynasty, the Guishuang (Kushana) King, belonged to Yue-chi tribe of central Asia. It is also believed present day Gujjar communities of India are also the descendants of Kushana Dynasty.
Kujula Kadphises (30 AD – 80 AD)
He killed the four other opponents of his to acquire the throne. He was a fearsome ruler who drove the Indo-Parthian out of Kabul and Anxi. He also defeated the kingdoms of Puda (Paktiya) and Gandhara. In 80 AD he was succeeded by his son, Sadashkana.
Vima Kadphises (95 AD –127 AD)
He was the grandson of the first ruler of Kujula Kadphises. He expanded the Kushana Empire futher southwards towards Afghanistan and Pakistan.
Kanishka I (127 AD – 140 AD)
Kanishka I is the most famous and the most respected king of Kushana Dynasty. Trade had reached its epitome during this time. Chinese empire had found a Silk Route to Rome which passed through Kushana Empire. Kanishka levied a tax on Silk Route. Furthermore, emphasis were laid on irrigation and it was considered a boon for the economy.
Kashishka also constructed a number of monuments such a 50 meter Buddha Statue in Afghanistan and a fort in Bhatinda. Kanishka ruled a huge empire from Kabul to Mathura. He ruled for only 13 years, but these years are considered the best times in Kushana History. He was succeeded by his son, Vasudeva I who ruled for around 35 years after which the whole empire started to decline.
After the death of Vasudeva I, Kushana Empire broke into two parts, Eastern Empire and the Western Empire, both facing problems of their own. The prolonged attacks from Sassanid from Persia had broken the backbone of Western Kushana Empire and that led to acquisition of Bactria at the hands of Indo- Sassanid. The Eastern Empire around Mathura was easily won by Samudragupta, the ruler of Gupta Empire in those times.