Gana-sanghas in course of time became the larger mahajanapadas and of the 16 kingdoms, Magadha eventually emerged as the most powerful.
The first known ruler of Magadha was Bimbisara, followed by his son Ajatashatru. Mahapadma Nanda started the Nanda dynasty.
The invasion of north-west India by Alexander in 326 BCE opened up trade with the West. After the death of Alexander, Chandragupta founded the Mauryan Empire.
The three notable Mauryan rulers, Chandragupta, Bindusara and Ashoka, established a centralised state. The system of Mauryan administration came to light through the accounts of Arthasastra and Indica.
Mauryan Empire set in a new phase in Indian history as trade and commerce grew manifold during this period.
Mauryan Empire continued the earlier tradition of consolidation of the empire. The truly revolutionary change that was attempted was Ashoka’s exhortations to his officials and people to follow dhamma, abjure violence and lead a moral life.
Mauryan Empire marked a distinct phase in Indian history with significant advances in technology and economic and social development, and created the framework for a large, centrally administered, state.