Ashoka ruled most of the Indian subcontinent in the third century before the common era, and he left an extraordinary thing behind: his own words, cut into rock faces and polished sandstone pillars across his empire, in the local languages of each region and in Greek and Aramaic on the northwestern frontier.
The thirteenth of the major rock edicts is the one that changed how he is read. In it the king describes the conquest of Kalinga, records the numbers deported, killed and dead of other causes, and states that he felt remorse, that the slaughter of even a hundredth of that number would now grieve him, and that he has turned to the pursuit of dhamma. Whatever else it is, it is a public statement by an ancient conqueror that a conquest was a moral failure, and there is nothing else quite like it in the ancient record.
The edicts announce a programme rather than a conversion narrative. They order officers to attend to the welfare of subjects, provide medical treatment for people and animals along the roads, plant trees and dig wells, restrict animal slaughter in the royal kitchen, and instruct that all religious communities be honoured and that praising one's own sect while disparaging another injures both. The inscriptions were unreadable for centuries until James Prinsep deciphered the script in the 1830s.