Emperor of the Maurya Empire who conquered most of the Indian subcontinent, was transformed by the violence of his wars, converted to Buddhism, and then ruled according to dhamma — a code of ethical governance — leaving behind the earliest major inscriptions in Indian history and one of the most influential examples of a ruler renouncing conquest.
Ashoka was the most powerful ruler in Indian history. He had just completed the bloodiest conquest of his reign when something changed. He wrote about it himself, on rocks and pillars across his empire: the Kalinga War had killed hundreds of thousands of people, and the sight of the suffering filled him with remorse. What followed — a deliberate attempt to govern through ethics rather than force, to send missionaries of non-violence to Hellenistic kings in Egypt and Greece — is unlike almost anything else in the ancient world. His edicts are still there, in stone, waiting to be read.