The Mauryan Empire

Out of Magadha's wreckage rose India's first pan-subcontinental empire, engineered by the ruthless strategist Chanakya on behalf of an ambitious young outsider, Chandragupta Maurya, who toppled the old dynasty and then met Alexander's heir Seleucus on the battlefield and came away with an empire stretching to the Hindu Kush — a treaty witnessed by the Greek envoy Megasthenes, whose account of the Mauryan court is the fullest outside description of ancient India that survives. Chandragupta's son Bindusara held the empire together and expanded it further south.

It was Bindusara's son Ashoka who transformed the dynasty's legacy entirely — a conqueror so horrified by the bloodshed of his own war against Kalinga that he renounced violence, embraced Buddhism, and carved edicts of tolerance and non-violence into pillars and rock faces across the subcontinent. Generations later, the philosopher Nagarjuna would give Ashoka's adopted faith its most rigorous philosophical foundation.