After the death of Asoka, his successors were not able to keep the vast Mauryan Empire intact. The provinces started declaring their independence. The northwest India slipped out of the control of the Mauryas and a series of foreign invasions affected this region. Kalinga declared its independence and in the further south the Satavahanas established their independent rule. As a result, the Mauryan rule was confined to the Gangetic valley and it was soon replaced by the Sunga dynasty.

Sungas

The founder of the Sunga dynasty was Pushyamitra Sunga, who was the commander-in-chief under the Mauryas. He assassinated the last Mauryan ruler and usurped the throne. The most important challenge to the Sunga rule was to protect north India against the invasions of the Bactrian Greeks from the northwest. The Greeks advanced up to Pataliputra and occupied it for sometime. However, Pushyamitra succeeded in regaining the lost territory. He also fought a campaign against Kharavela of Kalinga who invaded north India.

Pushyamitra was a staunch follower of Brahmanism. He performed two asvamedha sacrifices. Buddhist sources refer him as a persecutor of Buddhism. But there is enough evidence to show that Pushyamitra patronised Buddhist art. During his reign the Buddhist monuments at Bharhut and Sanchi were renovated and further improved.

After the death of Pushyamitra, his son Agnimitra became the ruler. The last Sunga ruler was Devabhuti, who was murdered by his minister Vasudeva Kanva, the founder of the Kanva dynasty. The Kanva dynasty ruled for 45 years. After the fall of the Kanvas, the history of Magatha was a blank until the establishment of the Gupta dynasty.

The rule of the Sungas was important because they defended the Gangetic valley from foreign invasions. In the cultural sphere, the Sungas revived Brahmanism and horse sacrifice. They also promoted the growth of Vaishnavism and the Sanskrit language. In short, the Sunga rule was a brilliant anticipation of the golden age of the Guptas.